Integrate rough estimate balance

AGENTS.md

@@ -615,6 +615,30 @@ Future sizing will need:
 
 Users must be able to override sizing suggestions.
 
+## Estimate Balance Module (Grobe Leistungsbilanz)
+
+`src/estimate-balance` plus `src/shared/estimate-balance` is a separate module
+for the early-phase power balance by DIN 276 cost group (see
+`docs/estimate-balance.md`). Rules:
+
+- It has its own tables (`estimate_*`) and never writes circuit, board or
+  project-device data; it only reads device rows for the comparison.
+- Writes use the project command mechanism (`estimate-balance.insert/.update/
+  .delete` with complete documents), so revision checks and Undo/Redo apply.
+- The calculation and comparison live in the import-free
+  `src/shared/estimate-balance/estimate-balance.ts` and are shared by API and UI;
+  displayed values use `roundEstimateValue`.
+- It is deliberately not part of named/automatic project snapshots or snapshot
+  restore; those operations leave estimate balances unchanged. Portable project
+  transfer format version 2 includes every estimate balance and remaps balance,
+  group and row ids when duplicating a project. Version 1 transfers remain
+  importable and contain no estimate balances.
+- UI: `/projects/:id/grobbilanz` (Stände) and `/grobbilanz/:balanceId` (editor,
+  `src/frontend/estimate-balance/`). The editor autosaves the whole document
+  debounced (one Undo step per save), keeps invalid raw input local, and on a
+  409 reloads only if the balance itself changed; otherwise it re-saves with
+  the new revision. `request()` throws `ApiRequestError` (status, code).
+
 ## Persistence and Migration Rules
 
 - SQLite is the currently supported database.

docs/README.md

@@ -16,6 +16,8 @@ ausdrücklich getrennt und dürfen nicht als bereits implementiert verstanden we
   Verteilerübersicht, Verteilerpläne, Büro-Logo
 - [Gebäudestruktur](building-structure.md) – Gebäude → Etagen → Räume,
   Befehle, Snapshot-Schema 7, eigene Seite
+- [Grobe Leistungsbilanz](estimate-balance.md) – LPH 2/3 nach Kostengruppen,
+  Rechnung, Vergleich mit der detaillierten Bilanz
 - [Editor-API](circuit-list-editor-api.md) – unterstützte Circuit-First-Endpunkte
 - [Bekannte Einschränkungen](circuit-list-editor-known-limitations.md) –
   bewusst noch nicht implementierte oder begrenzte Funktionen

docs/circuit-list-editor-api.md

@@ -59,6 +59,14 @@ this value for optimistic concurrency checks.
   - clients cannot submit arbitrary `project.restore-state` payloads through
     the generic command endpoint
 
+Grobbilanzen sind bewusst kein Teil dieser logischen Snapshots. Der portable
+Projektexport unter `GET /projects/:projectId/export` verwendet dagegen
+Transferformat 2 und enthält alle Grobbilanzen. Die beiden Importwege
+`POST /projects/:projectId/import` und `POST /projects/import` prüfen ihre
+Prüfsumme; Ersetzen übernimmt die Grobbilanzen atomar und mit Undo/Redo,
+Duplizieren vergibt neue IDs. Transferformat 1 bleibt ohne Grobbilanzen
+importierbar.
+
 The public dispatcher supports the Circuit and CircuitDeviceRow commands
 `circuit.update`, `circuit.insert`, `circuit.delete`,
 `circuit-device-row.update`, `circuit-device-row.insert`,
@@ -214,6 +222,12 @@ A stale `expectedRevision` returns HTTP `409` with
 `PROJECT_REVISION_CONFLICT`. Undo or redo without an eligible stack entry
 returns HTTP `409` with `PROJECT_HISTORY_OPERATION_UNAVAILABLE`.
 
+## Estimate Balance (Grobe Leistungsbilanz)
+
+Separate module under `/projects/:projectId/estimate-balances`; complete
+documents are written through `estimate-balance.insert/.update/.delete` project
+commands. Endpoints, payloads and calculation rules: `docs/estimate-balance.md`.
+
 ## Circuit-First Endpoints
 
 ### Distribution Board Setup

docs/current-architecture.md

@@ -290,15 +290,20 @@ Projektdaten und erzeugen keine Revisionen. Das Löschen eines Projektgeräts
 erfordert eine Bestätigung mit dessen Namen und verwendet weiterhin den
 bestehenden persistenten Projektbefehl.
 
-`GET /api/projects/:projectId/export` verpackt denselben vollständigen
-Projektzustand in ein portables, format- und schema-versioniertes JSON-Dokument
-mit SHA-256-Prüfsumme. `POST /api/projects/:projectId/import` prüft Format,
-Snapshot-Relationen und Prüfsumme vor jedem Schreibzugriff. Der Modus `replace`
-läuft über `project.restore-state` und ist dadurch eine atomare, dauerhaft
-rückgängig machbare Projektrevision. Der Modus `duplicate` ordnet Projekt-,
+`GET /api/projects/:projectId/export` verpackt den vollständigen portablen
+Projektzustand in ein format- und schema-versioniertes JSON-Dokument mit
+SHA-256-Prüfsumme. Transferformat 2 enthält zusätzlich alle Grobbilanzen,
+ohne sie in das logische Snapshot-Schema aufzunehmen; Format 1 bleibt ohne
+Grobbilanzen importierbar. `POST /api/projects/:projectId/import` prüft Format,
+Snapshot-Relationen, Grobbilanzen und Prüfsumme vor jedem Schreibzugriff. Der
+Modus `replace` läuft über `project.restore-state` Version 2 und ersetzt den
+Projektzustand und die Grobbilanzen atomar und dauerhaft rückgängig machbar.
+Normale Snapshot-Restores verwenden weiterhin Version 1 und lassen
+Grobbilanzen unverändert. Der Modus `duplicate` ordnet Projekt-,
 Struktur-, Gruppen-, Verteilerkomponenten-, Raum-, Stromkreis- und
-Gerätezeilen-UUIDs sowie Schutzgeräte-Referenzen vollständig neu zu und legt
-die Kopie mit Revision `0` in einer Transaktion an. Fachliche Verknüpfungen
+Gerätezeilen-UUIDs sowie Schutzgeräte-Referenzen und die IDs aller Grobbilanzen
+vollständig neu zu und legt die Kopie mit Revision `0` in einer Transaktion an.
+Fachliche Verknüpfungen
 innerhalb des unterstützten Laufzeitmodells bleiben
 erhalten. Die
 Projektübersicht verwendet dafür den separaten Collection-Endpunkt

docs/estimate-balance.md

@@ -0,0 +1,119 @@
+# Grobe Leistungsbilanz (LPH 2/3)
+
+Eigenes Modul für die Leistungsbilanz der Vor- und Entwurfsplanung, gegliedert
+nach Kostengruppen (DIN 276, KG 400). Es gibt dort noch keine Verteilungen und
+Stromkreise: Jedes Gewerk trägt unter seiner Kostengruppe Verbraucher als
+Stückzahl mit Einzelleistung oder als Fläche mit W/m² ein. Aufbau und Rechnung
+folgen der bisherigen Excel-Vorlage „Leistungsbilanz – KG400“. Abstimmung:
+Issue #7.
+
+Das Modul ist **nicht** mit der Stromkreisstruktur verknüpft. Es liest die
+Gerätezeilen nur für den Vergleich „geschätzt ↔ detailliert“ und schreibt
+nichts in Stromkreislisten, Verteilungen oder Projektgeräte.
+
+## Aufbau
+
+```
+src/shared/estimate-balance/estimate-balance.ts          Datenform, Rechnung, Vergleich (rein, ohne Imports)
+src/estimate-balance/domain/estimate-balance-command.model.ts   Snapshot-Schema (Zod), Befehle
+src/estimate-balance/domain/estimate-balance-project-command.store.ts   Store-Port
+src/estimate-balance/api/estimate-balance-request.schemas.ts   Request-Schemas
+src/db/schema/estimate-balances.ts                        Tabellen (Migration 0010)
+src/db/repositories/estimate-balance*.ts                  Lesen, Schreiben, Befehls-Store
+src/server/controllers/estimate-balance.controller.ts     API
+src/app/projects/[projectId]/grobbilanz/                  Übersicht der Stände und Editor
+src/frontend/estimate-balance/                            Editor-Komponenten und Helfer
+```
+
+Die gemeinsame Datei unter `src/shared/estimate-balance` hat keine Imports, weil
+das Frontend sie direkt nutzt (Turbopack löst die `.js`-Suffixe der API nicht auf).
+
+## Datenmodell
+
+| Tabelle | Inhalt |
+|---|---|
+| `estimate_balances` | ein **Stand** je Projekt (z. B. Vorplanung, Entwurfsplanung): Name, LPH, Datum, Reserve AV/SV in %, Sortierung |
+| `estimate_groups` | Kostengruppe (`"410"` … `"480"`, `""` für „Allgemein“), Titel, „bearbeitet von“, Sortierung |
+| `estimate_rows` | Versorgung (Auswahl ELT/MSR oder Freitext), Verbraucher/Fläche, Anzahl bzw. Fläche, Einheit (`piece` = St., `area` = m²), Anschluss (fest/Steckdose), Einzelleistung in W bzw. W/m², GLF, cos φ, SV ja/nein, Anmerkung |
+
+Neue Stände entstehen aus der Vorlage KG 400 (410 Sanitär, 420 Wärme, 430 Luft,
+434 Kälte, 440 Starkstrom, 450 Schwachstrom, 460 Förder, 470 Nutzungsspezifisch,
+480 GA, Allgemein; Reserve AV 10 %), leer oder als Kopie eines bestehenden
+Stands mit neuen IDs. Stände bleiben bearbeitbar; ein zusätzlicher Status oder
+eine Bearbeitungssperre ist derzeit nicht vorgesehen.
+
+## Rechnung
+
+- Zeile: P = Anzahl bzw. Fläche × Einzelleistung × GLF, S = P / cos φ.
+- **AV** enthält alle Verbraucher (Normalversorgung). **SV** listet zusätzlich
+  die Zeilen mit „SV = ja“, die auch aus der Sicherheitsstromversorgung versorgt
+  werden müssen. Das ist die Lesart der Vorlage; die Regel liegt in
+  `calculateEstimateRow` und lässt sich dort zentral ändern.
+- Summen je Kostengruppe, Gesamtsumme, Reserve in % (AV und SV getrennt),
+  Leistung inklusive Reserve und Maximalstrom I = S / (√3 · U) mit der
+  Drehstromspannung aus den Projekteinstellungen.
+- Anzeige wie in der Tabellenkalkulation gerundet (`roundEstimateValue`,
+  40,175 → 40,18). Der Test `tests/estimate-balance.test.ts` rechnet das
+  Beispiel der Vorlage vollständig nach (143,24 kW, 148,48 kVA, mit 10 %
+  Reserve 157,56 kW / 163,33 kVA, 235,75 A).
+
+## Vergleich geschätzt ↔ detailliert
+
+`GET …/comparison` summiert alle Gerätezeilen aller Stromkreislisten des
+Projekts (Anzahl × Leistung je Stück × Geräte-GZF, wie der Stromkreisbaum) und
+ordnet sie über das Feld **Kostengruppe** der Gerätezeile zu. Maßgeblich ist das
+längste passende Präfix: `434` → Gruppe 434, `431` → Gruppe 430, `444` → 440.
+Zeilen ohne passende Kostengruppe erscheinen als „nicht zugeordnet“. Der
+Verteiler-GZF wird auf keiner Seite angewendet; ein fehlendes cos φ zählt als 1.
+Verglichen wird die AV-Leistung (kW) mit Differenz absolut und in %.
+
+## Befehle, Undo/Redo
+
+Alle Änderungen laufen über den bestehenden Projekt-Befehlsmechanismus mit
+Revision, Inverse und persistentem Undo/Redo:
+
+- `estimate-balance.insert` / `estimate-balance.delete` mit dem vollständigen
+  Stand (Gruppen und Zeilen)
+- `estimate-balance.update` mit vollständigem `expected`/`target`-Dokument; der
+  Store prüft, dass der gespeicherte Stand genau `expected` entspricht, und
+  ersetzt ihn atomar. Die Inverse ist das vertauschte Paar.
+
+Der Editor speichert das ganze Dokument verzögert (Autosave); jeder
+Speichervorgang ist ein Undo-Schritt. Unveränderte Dokumente erzeugen keine
+Revision (`{ unchanged: true }`).
+
+## Projekttransfer und bewusste Abgrenzung
+
+- Das reguläre SQLite-Datenbank-Backup sichert die Grobbilanz-Tabellen zusammen
+  mit allen übrigen Anwendungsdaten.
+- Benannte und automatische Projektsnapshots enthalten keine Grobbilanzen; das
+  Snapshot-Schema bleibt Version 7. Snapshot-Restore und dessen Undo/Redo lassen
+  vorhandene Grobbilanzen unverändert.
+- Der portable Projektexport enthält alle Grobbilanzen ab Transferformat 2.
+  Ersetzen übernimmt sie atomar und rückgängig machbar; Duplizieren vergibt neue
+  IDs für Bilanz, Gruppen und Zeilen. Alte Transferdateien in Version 1 bleiben
+  importierbar und enthalten definitionsgemäß keine Grobbilanzen.
+- Keine Rechte je Gewerk; „bearbeitet von“ ist ein Freitext je Kostengruppe.
+- Kostengruppen der Gerätezeilen sind nicht normiert; der Vergleich arbeitet
+  mit Präfixen.
+- Der erste Vergleich zeigt die geschätzte und detaillierte AV-Wirkleistung in
+  kW. SV- und kVA-Vergleiche können später ergänzt werden.
+- Eine Stromkreisnummer gehört nicht zur Grobbilanz, weil sie eine frühe
+  Abschätzung ohne Stromkreisplanung ist.
+
+## API
+
+- `GET /api/projects/:projectId/estimate-balances`
+- `POST /api/projects/:projectId/estimate-balances` –
+  `{ "expectedRevision": 7, "name": "Entwurfsplanung", "workStage": "LPH 3", "dateIso": "2026-09-26", "template": "kg400" }`
+  (`template`: `kg400` | `empty` | `copy` mit `copyFromBalanceId`)
+- `GET /api/projects/:projectId/estimate-balances/:balanceId`
+- `PUT /api/projects/:projectId/estimate-balances/:balanceId` –
+  `{ "expectedRevision": 8, "balance": { …vollständiges Dokument… } }`
+- `DELETE /api/projects/:projectId/estimate-balances/:balanceId` – `{ "expectedRevision": 9 }`
+- `GET /api/projects/:projectId/estimate-balances/:balanceId/comparison`
+
+Validierung: Name 1–200 Zeichen, getrimmte Texte, Anzahl/Fläche und
+Einzelleistung ≥ 0, GLF 0–1, cos φ > 0 bis 1, Reserve 0–100 %, Datum
+`YYYY-MM-DD`, eindeutige Gruppen- und Zeilen-IDs, unbekannte Felder werden
+abgelehnt.

scripts/db-verify-circuit-schema.js

@@ -6,6 +6,9 @@ const db = new Database(dbPath, { readonly: true });
 
 const requiredTables = [
   "buildings",
+  "estimate_balances",
+  "estimate_groups",
+  "estimate_rows",
   "circuit_sections",
   "circuits",
   "circuit_device_rows",

src/app/globals.css

@@ -2002,3 +2002,710 @@ button.structure-entry-main:focus-visible {
   color: var(--color-ink-soft);
   font-size: 0.9rem;
 }
+
+/* ── Grobe Leistungsbilanz ──────────────────────────────────────────── */
+/* Tabelle im Stil der Büro-Vorlage „Leistungsbilanz – KG400“: kompakte
+   Zellen-Inputs statt Bootstrap-Formularfelder, Druck als A4 quer. */
+
+.estimate-toolbar {
+  display: flex;
+  align-items: center;
+  flex-wrap: wrap;
+  gap: var(--space-sm);
+}
+
+.estimate-save-status {
+  display: inline-flex;
+  align-items: center;
+  flex-wrap: wrap;
+  gap: var(--space-sm);
+  font-size: 0.8rem;
+}
+
+.estimate-save-badge {
+  display: inline-block;
+  padding: 0.2rem 0.55rem;
+  border-radius: 999px;
+  font-weight: 600;
+  border: 1px solid var(--color-border);
+  color: var(--color-ink-soft);
+  background: var(--color-bg);
+}
+
+.estimate-save-badge.is-saved {
+  color: var(--color-signal-dark);
+  border-color: var(--color-signal);
+}
+
+.estimate-save-badge.is-busy {
+  color: var(--color-warn);
+  border-color: var(--color-warn);
+}
+
+.estimate-save-badge.is-error {
+  color: var(--color-danger);
+  border-color: var(--color-danger);
+  background: var(--color-danger-bg);
+}
+
+.estimate-save-hint {
+  color: var(--color-danger);
+}
+
+.estimate-header-fields {
+  display: flex;
+  flex-wrap: wrap;
+  gap: var(--space-sm) var(--space-lg);
+  margin-bottom: var(--space-md);
+}
+
+.estimate-header-field {
+  display: flex;
+  align-items: center;
+  gap: var(--space-sm);
+  min-width: 10rem;
+}
+
+.estimate-header-field.is-wide {
+  flex: 1 1 18rem;
+}
+
+.estimate-header-label {
+  font-size: 0.7rem;
+  letter-spacing: 0.06em;
+  text-transform: uppercase;
+  font-weight: 600;
+  color: var(--color-ink-soft);
+}
+
+.estimate-header-value {
+  font-weight: 600;
+}
+
+.estimate-header-input {
+  font-size: 0.95rem;
+  font-weight: 600;
+  border-color: var(--panel-border);
+}
+
+.estimate-sheet-wrap {
+  overflow-x: auto;
+}
+
+.estimate-sheet {
+  width: 100%;
+  min-width: 1400px;
+  table-layout: fixed;
+  border-collapse: collapse;
+  font-size: 0.82rem;
+  background: var(--panel-bg);
+  color: var(--text-strong);
+}
+
+.estimate-comparison {
+  min-width: 640px;
+  table-layout: auto;
+}
+
+.estimate-sheet th,
+.estimate-sheet td {
+  border: 1px solid var(--panel-border);
+  padding: 2px 4px;
+  vertical-align: middle;
+}
+
+.estimate-sheet thead th {
+  background: var(--surface-header-row);
+  font-size: 0.72rem;
+  font-weight: 700;
+  text-align: center;
+  line-height: 1.2;
+}
+
+.estimate-th-hint {
+  display: block;
+  font-size: 0.68rem;
+  font-weight: 400;
+  color: var(--text-faint);
+}
+
+.estimate-col-kg { width: 3rem; }
+.estimate-col-supply { width: 4rem; }
+.estimate-col-name { width: auto; }
+.estimate-col-quantity { width: 4.8rem; }
+.estimate-col-unit { width: 3.8rem; }
+.estimate-col-connection { width: 5rem; }
+.estimate-col-power { width: 6.4rem; }
+.estimate-col-gzf { width: 6.8rem; }
+.estimate-col-cosphi { width: 3.8rem; }
+.estimate-col-result { width: 4.6rem; }
+.estimate-col-sv { width: 3.2rem; }
+.estimate-col-remark { width: 9rem; }
+.estimate-col-actions { width: 2.4rem; }
+
+.estimate-cell-input,
+.estimate-cell-select {
+  width: 100%;
+  min-width: 0;
+  border: 1px solid transparent;
+  border-radius: 3px;
+  background: transparent;
+  color: inherit;
+  font: inherit;
+  padding: 1px 4px;
+  line-height: 1.4;
+}
+
+.estimate-cell-select {
+  padding-right: 0;
+  cursor: pointer;
+}
+
+.estimate-cell-input:hover:not(:disabled),
+.estimate-cell-select:hover:not(:disabled) {
+  border-color: var(--panel-border-strong);
+}
+
+.estimate-cell-input:focus,
+.estimate-cell-select:focus {
+  outline: none;
+  border-color: var(--accent-blue);
+  background: var(--panel-bg);
+  box-shadow: 0 0 0 2px var(--accent-blue-soft-bg);
+}
+
+.estimate-cell-input.is-numeric {
+  text-align: right;
+  font-variant-numeric: tabular-nums;
+}
+
+.estimate-cell-input.is-invalid,
+.estimate-cell-input.is-invalid:focus,
+.estimate-cell-input.is-invalid:hover {
+  border-color: var(--color-danger);
+  background: var(--color-danger-bg);
+}
+
+.estimate-cell-input::placeholder {
+  color: var(--text-faint);
+  opacity: 0.7;
+}
+
+.estimate-unit-input,
+.estimate-gzf-input {
+  display: flex;
+  align-items: center;
+  gap: 2px;
+}
+
+.estimate-unit-label {
+  flex: 0 0 auto;
+  font-size: 0.7rem;
+  color: var(--text-faint);
+  min-width: 1.9rem;
+}
+
+.estimate-amev-button {
+  flex: 0 0 auto;
+  border: 1px solid var(--panel-border-strong);
+  border-radius: 3px;
+  background: var(--panel-bg-subtle);
+  color: var(--text-subtle);
+  font-size: 0.6rem;
+  font-weight: 700;
+  letter-spacing: 0.03em;
+  padding: 1px 3px;
+  line-height: 1.3;
+}
+
+.estimate-amev-button:hover:not(:disabled) {
+  border-color: var(--accent-blue);
+  color: var(--accent-blue);
+}
+
+.estimate-number {
+  text-align: right;
+  font-variant-numeric: tabular-nums;
+  white-space: nowrap;
+}
+
+.estimate-number.is-muted {
+  color: var(--text-faint);
+}
+
+.estimate-number.is-over {
+  color: var(--color-attention-dark);
+}
+
+.estimate-number.is-under {
+  color: var(--color-signal-dark);
+}
+
+.estimate-center {
+  text-align: center;
+}
+
+.estimate-cost-group-cell {
+  font-weight: 700;
+  text-align: center;
+  font-variant-numeric: tabular-nums;
+}
+
+.estimate-group-title-row td {
+  background: var(--surface-component-header);
+  font-weight: 700;
+}
+
+.estimate-group-title {
+  display: flex;
+  align-items: center;
+  flex-wrap: wrap;
+  gap: var(--space-xs) var(--space-lg);
+}
+
+.estimate-group-name {
+  font-size: 0.9rem;
+}
+
+.estimate-group-editor {
+  display: inline-flex;
+  align-items: center;
+  gap: var(--space-xs);
+  font-weight: 400;
+  font-size: 0.75rem;
+  color: var(--text-muted);
+}
+
+.estimate-group-editor .estimate-cell-input {
+  width: 12rem;
+}
+
+.estimate-group-actions {
+  display: flex;
+  justify-content: flex-end;
+  gap: 2px;
+}
+
+.estimate-group-title-row .estimate-actions-cell {
+  width: auto;
+  white-space: nowrap;
+}
+
+.estimate-icon-button {
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  padding: 0.15rem 0.3rem;
+  line-height: 1;
+}
+
+.estimate-actions-cell {
+  text-align: center;
+}
+
+.estimate-empty-row td {
+  color: var(--text-faint);
+  font-style: italic;
+}
+
+.estimate-subtotal-row td {
+  background: var(--panel-bg-subtle);
+  font-weight: 700;
+}
+
+.estimate-total-label {
+  text-align: right;
+  font-weight: 700;
+}
+
+.estimate-total-hint {
+  font-weight: 400;
+  color: var(--text-faint);
+}
+
+.estimate-total-row td {
+  background: var(--surface-header-row);
+  font-weight: 600;
+}
+
+.estimate-total-row.is-strong td {
+  font-weight: 800;
+  border-top: 2px solid var(--panel-border-strong);
+}
+
+.estimate-add-group-row td {
+  background: var(--panel-bg);
+  padding: var(--space-sm) 4px;
+}
+
+.estimate-unassigned-row td {
+  font-style: italic;
+  color: var(--text-muted);
+}
+
+.estimate-collapse-toggle {
+  display: inline-flex;
+  align-items: center;
+  gap: var(--space-xs);
+  border: 0;
+  background: transparent;
+  color: inherit;
+  font: inherit;
+  font-weight: 700;
+  padding: 0;
+}
+
+.estimate-list-table .estimate-number {
+  font-variant-numeric: tabular-nums;
+}
+
+/* Druck-Textwerte: auf dem Bildschirm unsichtbar, im Druck statt Inputs */
+.estimate-print-value {
+  display: none;
+}
+
+/* Ausrichtung: alle Zellen zentriert, nur „Verbraucher / Flächen“, die
+   Gruppentitel und die Summenbeschriftungen stehen links bzw. rechts. */
+.estimate-sheet td,
+.estimate-sheet td.estimate-number,
+.estimate-sheet .estimate-cell-input,
+.estimate-sheet .estimate-cell-input.is-numeric {
+  text-align: center;
+}
+
+.estimate-sheet .estimate-cell-select {
+  text-align: center;
+  text-align-last: center;
+}
+
+.estimate-sheet .estimate-unit-input,
+.estimate-sheet .estimate-gzf-input {
+  justify-content: center;
+}
+
+.estimate-sheet td.estimate-name-cell,
+.estimate-sheet td.estimate-name-cell .estimate-cell-input,
+.estimate-sheet .estimate-group-title-row td:not(.estimate-cost-group-cell),
+.estimate-comparison td:nth-child(2) {
+  text-align: left;
+}
+
+.estimate-sheet td.estimate-total-label {
+  text-align: right;
+}
+
+/* Druck im kbp-CD der Seitenansicht (src/frontend/print/print-document.css):
+   gleiche Farben, Schrift, Titelblock und Fußzeile. Die Fußzeile mit
+   Seitenzahlen setzt EstimatePrintHeader als @page-Regel mit Projektdaten. */
+.estimate-print-titleblock {
+  display: none;
+}
+
+@page estimate-balance {
+  size: A4 landscape;
+  margin: 10mm 10mm 13mm;
+}
+
+@media print {
+  body:has(.estimate-print-root) .sidebar,
+  .estimate-print-root .estimate-no-print,
+  .estimate-print-root .estimate-page-header,
+  .estimate-print-root .estimate-header-fields,
+  .estimate-print-root .alert,
+  .estimate-print-root input,
+  .estimate-print-root select,
+  .estimate-print-root button {
+    display: none !important;
+  }
+
+  html:has(.estimate-print-root),
+  body:has(.estimate-print-root),
+  body:has(.estimate-print-root) .app-shell,
+  body:has(.estimate-print-root) .app-shell-content {
+    background: #fff !important;
+  }
+
+  /* Der Dunkelmodus setzt color-scheme: dark; Chrome färbt damit auch den
+     Seitenrand dunkel. Im Druck gilt immer das helle Schema. */
+  html:has(.estimate-print-root) {
+    color-scheme: light !important;
+  }
+
+  .estimate-print-root .estimate-group-editor.is-empty {
+    display: none;
+  }
+
+  /* Verbraucher bekommt den Platz; Anmerkungen bleiben schmal. */
+  .estimate-sheet .estimate-col-name {
+    width: 52mm;
+  }
+
+  .estimate-sheet .estimate-col-remark {
+    width: 24mm;
+  }
+
+  .estimate-sheet .estimate-col-supply {
+    width: 13mm;
+  }
+
+  body:has(.estimate-print-root) .app-shell {
+    display: block;
+  }
+
+  .estimate-print-root {
+    --ep-blue: #476088;
+    --ep-lilac: #9198c4;
+    --ep-line: #d6dae5;
+    --ep-tint: #f5f6fa;
+    --ep-text: #2b2b2b;
+    --ep-muted: #6b7280;
+    --ep-accent: #c9782a;
+    page: estimate-balance;
+    padding: 0 !important;
+    max-width: none;
+    color: var(--ep-text);
+    font-family: Arial, "Helvetica Neue", Helvetica, sans-serif;
+    color-scheme: light;
+  }
+
+  .estimate-print-root * {
+    -webkit-print-color-adjust: exact;
+    print-color-adjust: exact;
+  }
+
+  .estimate-print-root .estimate-print-value {
+    display: inline;
+  }
+
+  /* Titelblock wie der Plankopf der Seitenansicht */
+  .estimate-print-titleblock {
+    display: grid;
+    grid-template-columns: 30mm 1fr auto auto;
+    margin-bottom: 4mm;
+    border: 1.5px solid var(--ep-blue);
+    background: #fff;
+    font-size: 8.5pt;
+    break-inside: avoid;
+  }
+
+  .estimate-print-titleblock > * {
+    padding: 2.5mm 3.5mm;
+    border-left: 1px solid var(--ep-line);
+  }
+
+  .estimate-print-titleblock > :first-child {
+    border-left: none;
+  }
+
+  .estimate-print-logo {
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    min-height: 16mm;
+    color: var(--ep-blue);
+    font-weight: bold;
+    text-align: center;
+  }
+
+  .estimate-print-logo img {
+    max-width: 100%;
+    max-height: 10mm;
+  }
+
+  .estimate-print-kicker {
+    color: var(--ep-muted);
+    font-size: 7pt;
+    letter-spacing: 0.05em;
+    text-transform: uppercase;
+  }
+
+  .estimate-print-heading {
+    display: flex;
+    align-items: baseline;
+    flex-wrap: wrap;
+    gap: 1mm 4mm;
+    margin-top: 1mm;
+  }
+
+  .estimate-print-stand {
+    color: var(--ep-blue);
+    font-size: 16pt;
+    font-weight: bold;
+  }
+
+  .estimate-print-project {
+    font-size: 12pt;
+    font-weight: bold;
+  }
+
+  .estimate-print-meta {
+    display: grid;
+    grid-template-columns: auto auto;
+    gap: 0.8mm 4mm;
+    align-content: center;
+    margin: 0;
+    font-size: 7.5pt;
+  }
+
+  .estimate-print-meta div {
+    display: contents;
+  }
+
+  .estimate-print-meta dt {
+    color: var(--ep-muted);
+    font-weight: normal;
+  }
+
+  .estimate-print-meta dd {
+    margin: 0;
+    font-weight: bold;
+  }
+
+  .estimate-print-meta.is-tinted {
+    background: var(--ep-tint);
+  }
+
+  /* Karten und Ränder der Bildschirmansicht entfallen */
+  .estimate-print-root .card {
+    border: 0;
+    box-shadow: none !important;
+    background: transparent;
+  }
+
+  .estimate-print-root .card-body,
+  .estimate-print-root .card-header {
+    padding: 0;
+    background: transparent;
+    border: 0;
+  }
+
+  .estimate-print-root .estimate-comparison-card {
+    margin-top: 6mm;
+    break-inside: avoid;
+  }
+
+  .estimate-print-root .estimate-comparison-card .card-header {
+    margin-bottom: 2mm;
+    color: var(--ep-blue);
+    font-size: 10pt;
+    font-weight: bold;
+  }
+
+  .estimate-sheet-wrap {
+    overflow: visible;
+  }
+
+  /* Tabelle */
+  .estimate-sheet {
+    min-width: 0;
+    table-layout: auto;
+    font-size: 7.4pt;
+    line-height: 1.2;
+    background: #fff;
+    color: var(--ep-text);
+  }
+
+  .estimate-sheet th,
+  .estimate-sheet td {
+    border: 1px solid var(--ep-line) !important;
+    padding: 0.7mm 1.5mm;
+    background: #fff;
+    color: var(--ep-text);
+  }
+
+  .estimate-sheet thead {
+    display: table-header-group;
+  }
+
+  .estimate-sheet thead th {
+    background: var(--ep-blue) !important;
+    border-color: var(--ep-blue) !important;
+    color: #fff !important;
+    font-weight: bold;
+    vertical-align: bottom;
+  }
+
+  .estimate-sheet thead .estimate-th-hint {
+    color: #dfe3f0 !important;
+  }
+
+  .estimate-group-title-row td {
+    background: var(--ep-tint) !important;
+    border-top: 1.5px solid var(--ep-lilac) !important;
+    font-weight: bold;
+  }
+
+  .estimate-group-title-row .estimate-cost-group-cell {
+    color: var(--ep-blue) !important;
+  }
+
+  .estimate-group-title-row .estimate-group-editor {
+    color: var(--ep-muted);
+    font-weight: normal;
+  }
+
+  .estimate-subtotal-row td {
+    border-bottom: 1.5px solid var(--ep-line) !important;
+    font-weight: bold;
+  }
+
+  .estimate-subtotal-row .estimate-total-label {
+    color: var(--ep-muted);
+  }
+
+  .estimate-total-row td {
+    background: var(--ep-tint) !important;
+    font-weight: bold;
+  }
+
+  .estimate-total-row.is-strong td {
+    background: var(--ep-blue) !important;
+    border-color: var(--ep-blue) !important;
+    color: #fff !important;
+  }
+
+  .estimate-total-row .estimate-total-hint {
+    color: var(--ep-muted);
+    font-weight: normal;
+  }
+
+  .estimate-total-row.is-strong .estimate-total-hint {
+    color: #dfe3f0;
+  }
+
+  .estimate-comparison .is-over {
+    color: var(--ep-accent) !important;
+    font-weight: bold;
+  }
+
+  .estimate-comparison .is-under {
+    color: var(--ep-blue) !important;
+    font-weight: bold;
+  }
+
+  .estimate-group-title-row,
+  .estimate-subtotal-row,
+  .estimate-total-row,
+  .estimate-row {
+    break-inside: avoid;
+  }
+
+  .estimate-group-title-row {
+    break-after: avoid;
+  }
+
+  /* Summen einmal am Ende, nicht auf jeder Seite */
+  .estimate-sheet tfoot {
+    display: table-row-group;
+    break-inside: avoid;
+  }
+
+  .estimate-col-actions {
+    width: 0;
+  }
+
+  .estimate-unit-input,
+  .estimate-gzf-input {
+    justify-content: center;
+  }
+}

src/app/projects/[projectId]/grobbilanz/[balanceId]/page.tsx

@@ -0,0 +1,745 @@
+"use client";
+
+import Link from "next/link";
+import { useParams, useRouter } from "next/navigation";
+import { type MouseEvent, useCallback, useEffect, useRef, useState } from "react";
+import {
+  ArrowLeft,
+  ChevronDown,
+  ChevronRight,
+  Printer,
+  Redo2,
+  RefreshCw,
+  Undo2,
+} from "lucide-react";
+import {
+  ApiRequestError,
+  getEstimateBalance,
+  getEstimateComparison,
+  getProject,
+  getProjectHistory,
+  isRevisionConflictError,
+  redoProjectCommand,
+  undoProjectCommand,
+  updateEstimateBalance,
+} from "../../../../../frontend/utils/api";
+import type {
+  EstimateBalanceDto,
+  EstimateComparisonDto,
+  ProjectDto,
+  ProjectHistoryStateDto,
+} from "../../../../../frontend/types";
+import type { EstimateGroupSnapshot } from "../../../../../shared/estimate-balance/estimate-balance";
+import { GzfPickerModal } from "../../../../../frontend/components/gzf-picker-modal";
+import {
+  addEstimateGroup,
+  estimateBalanceFingerprint,
+  estimateTextLimits,
+  normalizeEstimateSortOrder,
+  toSaveableEstimateBalance,
+  updateEstimateGroup,
+  updateEstimateRow,
+  validateEstimateBalance,
+} from "../../../../../frontend/estimate-balance/estimate-balance-document";
+import { formatIsoDateGerman } from "../../../../../frontend/estimate-balance/estimate-balance-format";
+import {
+  EstimateBalanceSheet,
+  type EstimateBalanceUpdate,
+} from "../../../../../frontend/estimate-balance/estimate-balance-sheet";
+import { EstimateComparisonTable } from "../../../../../frontend/estimate-balance/estimate-comparison-table";
+import { DraftInput } from "../../../../../frontend/estimate-balance/estimate-draft-input";
+import { EstimatePrintHeader } from "../../../../../frontend/estimate-balance/estimate-print-header";
+import {
+  EstimateGroupModal,
+  type EstimateGroupFormValues,
+} from "../../../../../frontend/estimate-balance/estimate-group-modal";
+
+const AUTOSAVE_DELAY_MS = 800;
+const CONFLICT_MESSAGE = "Die Bilanz wurde zwischenzeitlich geändert und neu geladen.";
+
+type SaveStatus = "saved" | "pending" | "saving" | "error" | "invalid";
+
+type GroupDialog = { group: EstimateGroupSnapshot | null };
+
+function errorMessage(error: unknown, fallback: string) {
+  return error instanceof Error && error.message ? error.message : fallback;
+}
+
+function isNotFoundError(error: unknown) {
+  return error instanceof ApiRequestError && error.status === 404;
+}
+
+export default function EstimateBalanceEditorPage() {
+  const params = useParams<{ projectId: string; balanceId: string }>();
+  const { projectId, balanceId } = params;
+  const router = useRouter();
+
+  const [project, setProject] = useState<ProjectDto | null>(null);
+  const [draft, setDraft] = useState<EstimateBalanceDto | null>(null);
+  const [history, setHistory] = useState<ProjectHistoryStateDto | null>(null);
+  const [comparison, setComparison] = useState<EstimateComparisonDto | null>(null);
+  const [comparisonError, setComparisonError] = useState<string | null>(null);
+  const [isComparisonOpen, setIsComparisonOpen] = useState(false);
+  const [saveStatus, setSaveStatus] = useState<SaveStatus>("saved");
+  const [saveError, setSaveError] = useState<string | null>(null);
+  const [error, setError] = useState<string | null>(null);
+  const [notice, setNotice] = useState<string | null>(null);
+  const [isLoading, setIsLoading] = useState(true);
+  const [isMissing, setIsMissing] = useState(false);
+  const [isHistoryBusy, setIsHistoryBusy] = useState(false);
+  const [invalidFieldKeys, setInvalidFieldKeys] = useState<ReadonlySet<string>>(
+    () => new Set()
+  );
+  const [groupDialog, setGroupDialog] = useState<GroupDialog | null>(null);
+  const [gzfTarget, setGzfTarget] = useState<{ groupId: string; rowId: string } | null>(
+    null
+  );
+
+  // Refs carry the latest values into timers, unload handlers and chained
+  // async saves without re-creating them.
+  const draftRef = useRef<EstimateBalanceDto | null>(null);
+  const revisionRef = useRef<number | null>(null);
+  const savedFingerprintRef = useRef<string | null>(null);
+  const saveInFlightRef = useRef<Promise<boolean> | null>(null);
+  const saveTimerRef = useRef<ReturnType<typeof setTimeout> | null>(null);
+
+  useEffect(() => {
+    draftRef.current = draft;
+  }, [draft]);
+
+  const applyServerBalance = useCallback((balance: EstimateBalanceDto) => {
+    const normalized = normalizeEstimateSortOrder(balance);
+    savedFingerprintRef.current = estimateBalanceFingerprint(normalized);
+    draftRef.current = normalized;
+    setDraft(normalized);
+    setSaveStatus("saved");
+    setSaveError(null);
+  }, []);
+
+  const reloadComparison = useCallback(async () => {
+    try {
+      setComparison(await getEstimateComparison(projectId, balanceId));
+      setComparisonError(null);
+    } catch (err) {
+      setComparisonError(
+        errorMessage(err, "Der Vergleich konnte nicht geladen werden.")
+      );
+    }
+  }, [balanceId, projectId]);
+
+  /** Reloads project, document and history; replaces the local draft. */
+  const reloadAll = useCallback(async () => {
+    const balanceRequest = getEstimateBalance(projectId, balanceId);
+    // Handled below; avoids an "unhandled rejection" while project/history load.
+    balanceRequest.catch(() => undefined);
+    // Project and history are applied even when the balance is missing, so
+    // Redo stays available after its creation was undone.
+    const [currentProject, currentHistory] = await Promise.all([
+      getProject(projectId),
+      getProjectHistory(projectId).catch(() => null),
+    ]);
+    setProject(currentProject);
+    revisionRef.current = currentHistory?.currentRevision ?? currentProject.currentRevision;
+    setHistory(currentHistory);
+    const balance = await balanceRequest;
+    applyServerBalance(balance);
+    setIsMissing(false);
+    void reloadComparison();
+  }, [applyServerBalance, balanceId, projectId, reloadComparison]);
+
+  const handleReloadError = useCallback((err: unknown) => {
+    if (isNotFoundError(err)) {
+      setIsMissing(true);
+      setDraft(null);
+      draftRef.current = null;
+      return;
+    }
+    setError(errorMessage(err, "Die grobe Leistungsbilanz konnte nicht geladen werden."));
+  }, []);
+
+  useEffect(() => {
+    if (!projectId || !balanceId) {
+      return;
+    }
+    setIsLoading(true);
+    reloadAll()
+      .then(() => setError(null))
+      .catch(handleReloadError)
+      .finally(() => setIsLoading(false));
+  }, [balanceId, handleReloadError, projectId, reloadAll]);
+
+  const clearSaveTimer = useCallback(() => {
+    if (saveTimerRef.current) {
+      clearTimeout(saveTimerRef.current);
+      saveTimerRef.current = null;
+    }
+  }, []);
+
+  /**
+   * Saves the current draft if it differs from the last saved state. Saves
+   * never overlap: a save requested while another runs waits for it and then
+   * saves whatever changed in the meantime. Resolves to false when the draft
+   * could not be saved.
+   */
+  const saveNow = useCallback(async (): Promise<boolean> => {
+    clearSaveTimer();
+    while (saveInFlightRef.current) {
+      await saveInFlightRef.current;
+    }
+    const current = draftRef.current;
+    const revision = revisionRef.current;
+    if (!current || revision === null) {
+      return true;
+    }
+    const fingerprint = estimateBalanceFingerprint(current);
+    if (fingerprint === savedFingerprintRef.current) {
+      setSaveStatus("saved");
+      return true;
+    }
+    const problems = validateEstimateBalance(current);
+    if (problems.length) {
+      setSaveStatus("invalid");
+      setSaveError(problems.join(" "));
+      return false;
+    }
+    const body = toSaveableEstimateBalance(current);
+
+    /**
+     * Another command changed the project revision. When this document is
+     * still unchanged on the server (e.g. an edit in a circuit list), the
+     * draft is kept and saved again; otherwise the server state wins.
+     */
+    async function resolveConflict(): Promise<"retry" | "reloaded"> {
+      const [currentProject, serverBalance, currentHistory] = await Promise.all([
+        getProject(projectId),
+        getEstimateBalance(projectId, balanceId),
+        getProjectHistory(projectId).catch(() => null),
+      ]);
+      setProject(currentProject);
+      setHistory(currentHistory);
+      revisionRef.current = currentHistory?.currentRevision ?? currentProject.currentRevision;
+      if (estimateBalanceFingerprint(serverBalance) === savedFingerprintRef.current) {
+        return "retry";
+      }
+      applyServerBalance(serverBalance);
+      setNotice(CONFLICT_MESSAGE);
+      void reloadComparison();
+      return "reloaded";
+    }
+
+    const run = (async () => {
+      setSaveStatus("saving");
+      for (let attempt = 0; ; attempt += 1) {
+        try {
+          const result = await updateEstimateBalance(
+            projectId,
+            body,
+            attempt === 0 ? revision : revisionRef.current ?? revision
+          );
+          if (!("unchanged" in result)) {
+            revisionRef.current = result.history.currentRevision;
+            setHistory(result.history);
+            setProject((currentProject) =>
+              currentProject
+                ? { ...currentProject, currentRevision: result.history.currentRevision }
+                : currentProject
+            );
+          }
+          // The sent document is the saved state; the local draft is kept so
+          // typing is never interrupted by the server's copy.
+          savedFingerprintRef.current = fingerprint;
+          setSaveError(null);
+          const latest = draftRef.current;
+          if (latest && estimateBalanceFingerprint(latest) !== fingerprint) {
+            setSaveStatus("pending");
+          } else {
+            setSaveStatus("saved");
+          }
+          void reloadComparison();
+          return true;
+        } catch (err) {
+          if (isRevisionConflictError(err)) {
+            try {
+              if (attempt === 0 && (await resolveConflict()) === "retry") {
+                continue;
+              }
+              if (attempt > 0) {
+                await reloadAll();
+                setNotice(CONFLICT_MESSAGE);
+              }
+            } catch (reloadError) {
+              handleReloadError(reloadError);
+            }
+            return false;
+          }
+          if (isNotFoundError(err)) {
+            handleReloadError(err);
+            return false;
+          }
+          setSaveStatus("error");
+          setSaveError(errorMessage(err, "Die Änderungen konnten nicht gespeichert werden."));
+          return false;
+        }
+      }
+    })();
+    saveInFlightRef.current = run;
+    try {
+      return await run;
+    } finally {
+      saveInFlightRef.current = null;
+    }
+  }, [
+    applyServerBalance,
+    balanceId,
+    clearSaveTimer,
+    handleReloadError,
+    projectId,
+    reloadAll,
+    reloadComparison,
+  ]);
+
+  // Debounced autosave after every change of the draft.
+  useEffect(() => {
+    if (!draft) {
+      return;
+    }
+    if (estimateBalanceFingerprint(draft) === savedFingerprintRef.current) {
+      return;
+    }
+    setSaveStatus((status) => (status === "saving" ? status : "pending"));
+    clearSaveTimer();
+    saveTimerRef.current = setTimeout(() => {
+      saveTimerRef.current = null;
+      void saveNow();
+    }, AUTOSAVE_DELAY_MS);
+    return clearSaveTimer;
+  }, [clearSaveTimer, draft, saveNow]);
+
+  // Save immediately when the tab is hidden; on unload/unmount send the last
+  // change with keepalive so it survives the page.
+  useEffect(() => {
+    function hasUnsavedDraft() {
+      const current = draftRef.current;
+      return Boolean(
+        current && estimateBalanceFingerprint(current) !== savedFingerprintRef.current
+      );
+    }
+    function sendKeepalive(): boolean {
+      const current = draftRef.current;
+      const revision = revisionRef.current;
+      if (
+        !current ||
+        revision === null ||
+        saveInFlightRef.current ||
+        validateEstimateBalance(current).length
+      ) {
+        return false;
+      }
+      savedFingerprintRef.current = estimateBalanceFingerprint(current);
+      void updateEstimateBalance(projectId, toSaveableEstimateBalance(current), revision, {
+        keepalive: true,
+      }).catch(() => undefined);
+      return true;
+    }
+    function handleVisibilityChange() {
+      if (document.visibilityState === "hidden" && hasUnsavedDraft()) {
+        void saveNow();
+      }
+    }
+    function handleBeforeUnload(event: BeforeUnloadEvent) {
+      if (!hasUnsavedDraft() || sendKeepalive()) {
+        return;
+      }
+      // A save is still running or the draft is invalid: let the browser ask.
+      event.preventDefault();
+      event.returnValue = "";
+    }
+    document.addEventListener("visibilitychange", handleVisibilityChange);
+    window.addEventListener("beforeunload", handleBeforeUnload);
+    return () => {
+      document.removeEventListener("visibilitychange", handleVisibilityChange);
+      window.removeEventListener("beforeunload", handleBeforeUnload);
+      // In-app navigation (e.g. sidebar) unmounts the editor.
+      if (hasUnsavedDraft()) {
+        sendKeepalive();
+      }
+    };
+  }, [projectId, saveNow]);
+
+  const handleChange: EstimateBalanceUpdate = useCallback((update) => {
+    setNotice(null);
+    setDraft((current) => (current ? update(current) : current));
+  }, []);
+
+  const handleValidityChange = useCallback((fieldKey: string, isValid: boolean) => {
+    setInvalidFieldKeys((current) => {
+      if (isValid ? !current.has(fieldKey) : current.has(fieldKey)) {
+        return current;
+      }
+      const next = new Set(current);
+      if (isValid) {
+        next.delete(fieldKey);
+      } else {
+        next.add(fieldKey);
+      }
+      return next;
+    });
+  }, []);
+
+  async function handleHistory(direction: "undo" | "redo") {
+    setError(null);
+    setNotice(null);
+    setIsHistoryBusy(true);
+    try {
+      // Pending edits are saved first so they become their own undo step.
+      await saveNow();
+      const revision = revisionRef.current;
+      if (revision === null) {
+        return;
+      }
+      const result =
+        direction === "undo"
+          ? await undoProjectCommand(projectId, revision)
+          : await redoProjectCommand(projectId, revision);
+      revisionRef.current = result.history.currentRevision;
+      setHistory(result.history);
+      await reloadAll();
+    } catch (err) {
+      if (isRevisionConflictError(err)) {
+        await reloadAll().catch(handleReloadError);
+        setNotice(CONFLICT_MESSAGE);
+      } else if (isNotFoundError(err)) {
+        handleReloadError(err);
+      } else {
+        setError(
+          errorMessage(
+            err,
+            direction === "undo"
+              ? "Die letzte Änderung konnte nicht rückgängig gemacht werden."
+              : "Die letzte Änderung konnte nicht wiederholt werden."
+          )
+        );
+      }
+    } finally {
+      setIsHistoryBusy(false);
+    }
+  }
+
+  async function handleBackClick(event: MouseEvent<HTMLAnchorElement>) {
+    const current = draftRef.current;
+    if (!current || estimateBalanceFingerprint(current) === savedFingerprintRef.current) {
+      return;
+    }
+    event.preventDefault();
+    await saveNow();
+    router.push(`/projects/${projectId}/grobbilanz`);
+  }
+
+  function handleSaveGroup(values: EstimateGroupFormValues) {
+    const editingGroup = groupDialog?.group ?? null;
+    handleChange((current) =>
+      editingGroup
+        ? updateEstimateGroup(current, editingGroup.id, values)
+        : addEstimateGroup(current, values).balance
+    );
+    setGroupDialog(null);
+  }
+
+  function handleSelectGzf(value: number) {
+    if (gzfTarget) {
+      handleChange((current) =>
+        updateEstimateRow(current, gzfTarget.groupId, gzfTarget.rowId, {
+          simultaneityFactor: value,
+        })
+      );
+    }
+    setGzfTarget(null);
+  }
+
+  const isEditingDisabled = !draft || isHistoryBusy;
+  const invalidCount = invalidFieldKeys.size;
+  const listHref = `/projects/${projectId}/grobbilanz`;
+
+  return (
+    <main className="container-fluid py-4 estimate-print-root">
+      {project && draft ? <EstimatePrintHeader balance={draft} project={project} /> : null}
+      <div className="page-header estimate-page-header">
+        <div className="d-flex align-items-start gap-3">
+          <Link
+            aria-label="Zurück zur Übersicht der Stände"
+            className="btn btn-outline-secondary btn-sm structure-back-link estimate-no-print"
+            href={listHref}
+            onClick={(event) => void handleBackClick(event)}
+            title="Zurück zur Übersicht der Stände"
+          >
+            <ArrowLeft aria-hidden="true" size={18} />
+          </Link>
+          <div>
+            <div className="kicker">{project?.name ?? "Projekt"}</div>
+            <h1>Grobe Leistungsbilanz{draft ? ` – ${draft.name}` : ""}</h1>
+            <p className="text-secondary mb-0 estimate-no-print">
+              Leistungsabschätzung nach Kostengruppen (DIN 276) für LPH 2/3.
+            </p>
+          </div>
+        </div>
+        <div className="estimate-toolbar estimate-no-print">
+          <SaveStatusBadge
+            error={saveError}
+            invalidCount={invalidCount}
+            onRetry={() => void saveNow()}
+            status={saveStatus}
+          />
+          <div className="btn-group btn-group-sm" role="group" aria-label="Verlauf">
+            <button
+              aria-label="Rückgängig"
+              className="btn btn-outline-secondary"
+              disabled={isHistoryBusy || !history || history.undoDepth === 0}
+              onClick={() => void handleHistory("undo")}
+              title="Rückgängig (letzte Änderung im Projekt)"
+              type="button"
+            >
+              <Undo2 aria-hidden="true" size={16} />
+            </button>
+            <button
+              aria-label="Wiederholen"
+              className="btn btn-outline-secondary"
+              disabled={isHistoryBusy || !history || history.redoDepth === 0}
+              onClick={() => void handleHistory("redo")}
+              title="Wiederholen (im Projekt)"
+              type="button"
+            >
+              <Redo2 aria-hidden="true" size={16} />
+            </button>
+          </div>
+          <button
+            aria-label="Drucken"
+            className="btn btn-sm btn-outline-secondary"
+            disabled={!draft}
+            onClick={() => window.print()}
+            title="Drucken"
+            type="button"
+          >
+            <Printer aria-hidden="true" className="me-1" size={16} />
+            Drucken
+          </button>
+        </div>
+      </div>
+
+      {notice ? (
+        <div className="alert alert-info estimate-no-print" role="status">
+          {notice}
+        </div>
+      ) : null}
+      {error ? (
+        <div className="alert alert-warning estimate-no-print" role="alert">
+          {error}
+        </div>
+      ) : null}
+      {isLoading ? (
+        <p className="text-secondary" role="status">
+          Grobe Leistungsbilanz wird geladen …
+        </p>
+      ) : null}
+      {isMissing ? (
+        <div className="alert alert-warning" role="alert">
+          Dieser Stand existiert nicht (mehr), z. B. weil er gelöscht oder sein Anlegen
+          rückgängig gemacht wurde.{" "}
+          <Link href={listHref}>Zur Übersicht der Stände</Link>
+        </div>
+      ) : null}
+
+      {draft && project ? (
+        <>
+          <section className="card shadow-sm mb-3 estimate-sheet-card">
+            <div className="card-body">
+              <div className="estimate-header-fields">
+                <div className="estimate-header-field">
+                  <span className="estimate-header-label">Projekt</span>
+                  <span className="estimate-header-value">{project.name}</span>
+                </div>
+                <label className="estimate-header-field is-wide">
+                  <span className="estimate-header-label">Stand</span>
+                  <DraftInput
+                    ariaLabel="Bezeichnung des Stands"
+                    className="estimate-cell-input estimate-header-input"
+                    disabled={isEditingDisabled}
+                    format={(value: string) => value}
+                    maxLength={estimateTextLimits.balanceName}
+                    onCommit={(name) => handleChange((current) => ({ ...current, name }))}
+                    onValidityChange={(isValid) =>
+                      handleValidityChange("balance:name", isValid)
+                    }
+                    parse={(text) =>
+                      text.trim()
+                        ? { ok: true, value: text }
+                        : { ok: false, error: "Die Bezeichnung darf nicht leer sein." }
+                    }
+                    value={draft.name}
+                  />
+                </label>
+                <label className="estimate-header-field">
+                  <span className="estimate-header-label">LPH</span>
+                  <input
+                    aria-label="Leistungsphase"
+                    className="estimate-cell-input estimate-header-input"
+                    disabled={isEditingDisabled}
+                    maxLength={estimateTextLimits.workStage}
+                    onChange={(event) =>
+                      handleChange((current) => ({
+                        ...current,
+                        workStage: event.target.value,
+                      }))
+                    }
+                    placeholder="z. B. LPH 3"
+                    type="text"
+                    value={draft.workStage ?? ""}
+                  />
+                  <span className="estimate-print-value">{draft.workStage ?? ""}</span>
+                </label>
+                <label className="estimate-header-field">
+                  <span className="estimate-header-label">Datum</span>
+                  <input
+                    aria-label="Datum"
+                    className="estimate-cell-input estimate-header-input"
+                    disabled={isEditingDisabled}
+                    onChange={(event) =>
+                      handleChange((current) => ({
+                        ...current,
+                        dateIso: event.target.value || null,
+                      }))
+                    }
+                    type="date"
+                    value={draft.dateIso ?? ""}
+                  />
+                  <span className="estimate-print-value">
+                    {formatIsoDateGerman(draft.dateIso)}
+                  </span>
+                </label>
+              </div>
+              <EstimateBalanceSheet
+                balance={draft}
+                disabled={isEditingDisabled}
+                onAddGroup={() => setGroupDialog({ group: null })}
+                onChange={handleChange}
+                onEditGroup={(group) => setGroupDialog({ group })}
+                onOpenGzfPicker={(groupId, rowId) => setGzfTarget({ groupId, rowId })}
+                onValidityChange={handleValidityChange}
+                threePhaseVoltageV={project.threePhaseVoltageV}
+              />
+            </div>
+          </section>
+
+          <section
+            className={
+              isComparisonOpen
+                ? "card shadow-sm estimate-comparison-card"
+                : "card shadow-sm estimate-comparison-card estimate-no-print"
+            }
+          >
+            <div className="card-header d-flex justify-content-between align-items-center gap-2">
+              <button
+                aria-controls="estimate-comparison-body"
+                aria-expanded={isComparisonOpen}
+                className="estimate-collapse-toggle"
+                onClick={() => setIsComparisonOpen((open) => !open)}
+                type="button"
+              >
+                {isComparisonOpen ? (
+                  <ChevronDown aria-hidden="true" size={16} />
+                ) : (
+                  <ChevronRight aria-hidden="true" size={16} />
+                )}
+                Vergleich mit detaillierter Bilanz
+              </button>
+              {isComparisonOpen ? (
+                <button
+                  aria-label="Vergleich neu laden"
+                  className="btn btn-sm btn-outline-secondary structure-icon-button estimate-no-print"
+                  onClick={() => void reloadComparison()}
+                  title="Vergleich neu laden"
+                  type="button"
+                >
+                  <RefreshCw aria-hidden="true" size={14} />
+                </button>
+              ) : null}
+            </div>
+            {isComparisonOpen ? (
+              <div className="card-body" id="estimate-comparison-body">
+                {comparisonError ? (
+                  <div className="alert alert-warning" role="alert">
+                    {comparisonError}
+                  </div>
+                ) : null}
+                {comparison ? <EstimateComparisonTable comparison={comparison} /> : null}
+                <p className="text-secondary small mt-2 mb-0">
+                  Detailliert = Summe der Gerätezeilen aller Stromkreislisten (Anzahl ×
+                  Leistung × Geräte-GZF), zugeordnet über die Kostengruppe; ohne
+                  Verteiler-GZF.
+                </p>
+              </div>
+            ) : null}
+          </section>
+        </>
+      ) : null}
+
+      {groupDialog ? (
+        <EstimateGroupModal
+          group={groupDialog.group}
+          onClose={() => setGroupDialog(null)}
+          onSave={handleSaveGroup}
+        />
+      ) : null}
+      {gzfTarget ? (
+        <GzfPickerModal onClose={() => setGzfTarget(null)} onSelect={handleSelectGzf} />
+      ) : null}
+    </main>
+  );
+}
+
+function SaveStatusBadge({
+  error,
+  invalidCount,
+  onRetry,
+  status,
+}: {
+  error: string | null;
+  invalidCount: number;
+  onRetry: () => void;
+  status: SaveStatus;
+}) {
+  const label =
+    status === "saving"
+      ? "Wird gespeichert …"
+      : status === "pending"
+        ? "Ungespeicherte Änderungen"
+        : status === "error"
+          ? "Nicht gespeichert – Fehler"
+          : status === "invalid"
+            ? "Nicht gespeichert – ungültige Eingaben"
+            : "Gespeichert";
+  const tone =
+    status === "error" || status === "invalid"
+      ? "is-error"
+      : status === "saved"
+        ? "is-saved"
+        : "is-busy";
+  return (
+    <div className="estimate-save-status" role="status" aria-live="polite">
+      <span className={`estimate-save-badge ${tone}`} title={error ?? undefined}>
+        {label}
+      </span>
+      {invalidCount ? (
+        <span className="estimate-save-hint">
+          {invalidCount === 1
+            ? "1 ungültige Eingabe wird nicht gespeichert"
+            : `${invalidCount} ungültige Eingaben werden nicht gespeichert`}
+        </span>
+      ) : null}
+      {status === "error" ? (
+        <button className="btn btn-link btn-sm p-0" onClick={onRetry} type="button">
+          Erneut versuchen
+        </button>
+      ) : null}
+    </div>
+  );
+}

src/app/projects/[projectId]/grobbilanz/page.tsx

@@ -0,0 +1,292 @@
+"use client";
+
+import Link from "next/link";
+import { useParams, useRouter } from "next/navigation";
+import { useCallback, useEffect, useState } from "react";
+import { ArrowLeft, Copy, FolderOpen, Plus, Trash2 } from "lucide-react";
+import {
+  createEstimateBalance,
+  deleteEstimateBalance,
+  getProject,
+  listEstimateBalances,
+} from "../../../../frontend/utils/api";
+import type {
+  CreateEstimateBalanceInput,
+  EstimateBalanceDto,
+  ProjectCommandResultDto,
+  ProjectDto,
+} from "../../../../frontend/types";
+import { calculateEstimateBalance } from "../../../../shared/estimate-balance/estimate-balance";
+import {
+  EstimateBalanceCreateModal,
+  type EstimateBalanceCreateDefaults,
+} from "../../../../frontend/estimate-balance/estimate-balance-create-modal";
+import { createCopyName } from "../../../../frontend/estimate-balance/estimate-balance-document";
+import {
+  formatIsoDateGerman,
+  formatKw,
+} from "../../../../frontend/estimate-balance/estimate-balance-format";
+
+function countRows(balance: EstimateBalanceDto) {
+  return balance.groups.reduce((sum, group) => sum + group.rows.length, 0);
+}
+
+export default function EstimateBalanceListPage() {
+  const params = useParams<{ projectId: string }>();
+  const projectId = params.projectId;
+  const router = useRouter();
+  const [project, setProject] = useState<ProjectDto | null>(null);
+  const [balances, setBalances] = useState<EstimateBalanceDto[]>([]);
+  const [createDefaults, setCreateDefaults] =
+    useState<EstimateBalanceCreateDefaults | null>(null);
+  const [error, setError] = useState<string | null>(null);
+  const [isLoading, setIsLoading] = useState(true);
+  const [isSaving, setIsSaving] = useState(false);
+
+  const reload = useCallback(async () => {
+    const [currentProject, loadedBalances] = await Promise.all([
+      getProject(projectId),
+      listEstimateBalances(projectId),
+    ]);
+    setProject(currentProject);
+    setBalances([...loadedBalances].sort((left, right) => left.sortOrder - right.sortOrder));
+  }, [projectId]);
+
+  useEffect(() => {
+    if (!projectId) {
+      return;
+    }
+    setIsLoading(true);
+    reload()
+      .then(() => setError(null))
+      .catch((err: unknown) =>
+        setError(
+          err instanceof Error
+            ? err.message
+            : "Grobe Leistungsbilanzen konnten nicht geladen werden."
+        )
+      )
+      .finally(() => setIsLoading(false));
+  }, [projectId, reload]);
+
+  async function runCommand<TResult extends ProjectCommandResultDto>(
+    execute: (expectedRevision: number) => Promise<TResult>,
+    fallbackMessage: string
+  ): Promise<TResult | null> {
+    if (!project) {
+      return null;
+    }
+    setIsSaving(true);
+    setError(null);
+    try {
+      const result = await execute(project.currentRevision);
+      setProject((current) =>
+        current ? { ...current, currentRevision: result.history.currentRevision } : current
+      );
+      await reload();
+      return result;
+    } catch (err) {
+      setError(err instanceof Error ? err.message : fallbackMessage);
+      // Refresh revision and list so a stale state does not block the next
+      // attempt; the command error stays visible.
+      await reload().catch(() => undefined);
+      return null;
+    } finally {
+      setIsSaving(false);
+    }
+  }
+
+  async function handleCreate(input: CreateEstimateBalanceInput) {
+    const result = await runCommand(
+      (expectedRevision) => createEstimateBalance(projectId, input, expectedRevision),
+      "Stand konnte nicht angelegt werden."
+    );
+    if (result) {
+      setCreateDefaults(null);
+      router.push(`/projects/${projectId}/grobbilanz/${result.balance.id}`);
+    }
+  }
+
+  async function handleDelete(balance: EstimateBalanceDto) {
+    if (
+      !window.confirm(
+        `Stand „${balance.name}“ der groben Leistungsbilanz wirklich löschen?`
+      )
+    ) {
+      return;
+    }
+    await runCommand(
+      (expectedRevision) => deleteEstimateBalance(projectId, balance.id, expectedRevision),
+      "Stand konnte nicht gelöscht werden."
+    );
+  }
+
+  const isBusy = isSaving || !project;
+  const voltage = project?.threePhaseVoltageV ?? 400;
+
+  return (
+    <main className="container py-4">
+      <div className="page-header">
+        <div className="d-flex align-items-start gap-3">
+          <Link
+            aria-label="Zurück zur Projektübersicht"
+            className="btn btn-outline-secondary btn-sm structure-back-link"
+            href={`/projects/${projectId}`}
+            title="Zurück zur Projektübersicht"
+          >
+            <ArrowLeft aria-hidden="true" size={18} />
+          </Link>
+          <div>
+            <div className="kicker">{project?.name ?? "Projekt"}</div>
+            <h1>Grobe Leistungsbilanz</h1>
+            <p className="text-secondary mb-0">
+              Leistungsabschätzung für Vor- und Entwurfsplanung (LPH 2/3), gegliedert nach
+              Kostengruppen der DIN 276 – unabhängig von den Stromkreislisten.
+            </p>
+          </div>
+        </div>
+        <button
+          className="btn btn-primary"
+          disabled={isBusy}
+          onClick={() => setCreateDefaults({})}
+          type="button"
+        >
+          <Plus aria-hidden="true" className="me-1" size={16} />
+          Neuer Stand
+        </button>
+      </div>
+
+      {error ? (
+        <div className="alert alert-warning" role="alert">
+          {error}
+        </div>
+      ) : null}
+      {isLoading ? (
+        <p className="text-secondary" role="status">
+          Grobe Leistungsbilanzen werden geladen …
+        </p>
+      ) : null}
+
+      <section aria-labelledby="estimate-list-heading" className="card shadow-sm">
+        <div className="card-header d-flex justify-content-between align-items-center">
+          <h2 className="structure-column-title" id="estimate-list-heading">
+            Stände
+            <span className="badge text-bg-secondary ms-2">{balances.length}</span>
+          </h2>
+        </div>
+        {balances.length ? (
+          <div className="table-responsive">
+            <table className="table table-hover align-middle mb-0 estimate-list-table">
+              <thead>
+                <tr>
+                  <th>Stand</th>
+                  <th>LPH</th>
+                  <th>Datum</th>
+                  <th className="text-end">AV kW</th>
+                  <th className="text-end">AV kVA</th>
+                  <th className="text-end">SV kW</th>
+                  <th className="text-end">SV kVA</th>
+                  <th className="text-end">Aktionen</th>
+                </tr>
+              </thead>
+              <tbody>
+                {balances.map((balance) => {
+                  const result = calculateEstimateBalance(balance, voltage);
+                  const href = `/projects/${projectId}/grobbilanz/${balance.id}`;
+                  const rowCount = countRows(balance);
+                  return (
+                    <tr key={balance.id}>
+                      <td>
+                        <Link className="fw-semibold" href={href}>
+                          {balance.name}
+                        </Link>
+                        <div className="text-secondary small">
+                          {balance.groups.length} Kostengruppen ·{" "}
+                          {rowCount === 1 ? "1 Zeile" : `${rowCount} Zeilen`}
+                        </div>
+                      </td>
+                      <td>{balance.workStage ?? "–"}</td>
+                      <td>{formatIsoDateGerman(balance.dateIso)}</td>
+                      <td className="text-end estimate-number">
+                        {formatKw(result.withReserve.av.kw)}
+                      </td>
+                      <td className="text-end estimate-number">
+                        {formatKw(result.withReserve.av.kva)}
+                      </td>
+                      <td className="text-end estimate-number">
+                        {formatKw(result.withReserve.sv.kw)}
+                      </td>
+                      <td className="text-end estimate-number">
+                        {formatKw(result.withReserve.sv.kva)}
+                      </td>
+                      <td className="text-end">
+                        <div className="d-inline-flex gap-1">
+                          <Link
+                            aria-label={`Stand „${balance.name}“ öffnen`}
+                            className="btn btn-sm btn-outline-primary"
+                            href={href}
+                            title="Öffnen"
+                          >
+                            <FolderOpen aria-hidden="true" className="me-1" size={14} />
+                            Öffnen
+                          </Link>
+                          <button
+                            aria-label={`Stand „${balance.name}“ als neuen Stand kopieren`}
+                            className="btn btn-sm btn-outline-secondary structure-icon-button"
+                            disabled={isBusy}
+                            onClick={() =>
+                              setCreateDefaults({
+                                name: createCopyName(balance.name),
+                                workStage: balance.workStage,
+                                template: "copy",
+                                copyFromBalanceId: balance.id,
+                              })
+                            }
+                            title="Als neuen Stand kopieren"
+                            type="button"
+                          >
+                            <Copy aria-hidden="true" size={14} />
+                          </button>
+                          <button
+                            aria-label={`Stand „${balance.name}“ löschen`}
+                            className="btn btn-sm btn-outline-danger structure-icon-button"
+                            disabled={isBusy}
+                            onClick={() => void handleDelete(balance)}
+                            title="Stand löschen"
+                            type="button"
+                          >
+                            <Trash2 aria-hidden="true" size={14} />
+                          </button>
+                        </div>
+                      </td>
+                    </tr>
+                  );
+                })}
+              </tbody>
+            </table>
+            <p className="text-secondary small px-3 py-2 mb-0">
+              Leistungen jeweils inklusive Reserve.
+            </p>
+          </div>
+        ) : !isLoading ? (
+          <div className="card-body">
+            <p className="structure-empty mb-0">
+              Noch kein Stand vorhanden. Mit „Neuer Stand“ eine grobe Leistungsbilanz auf
+              Basis der Vorlage KG 400 anlegen.
+            </p>
+          </div>
+        ) : null}
+      </section>
+
+      {createDefaults ? (
+        <EstimateBalanceCreateModal
+          balances={balances}
+          defaults={createDefaults}
+          isSaving={isSaving}
+          onClose={() => setCreateDefaults(null)}
+          onCreate={(input) => void handleCreate(input)}
+        />
+      ) : null}
+    </main>
+  );
+}

src/db/migrations/0010_estimate_balances.sql

@@ -0,0 +1,42 @@
+CREATE TABLE `estimate_balances` (
+	`id` text PRIMARY KEY NOT NULL,
+	`project_id` text NOT NULL,
+	`name` text NOT NULL,
+	`work_stage` text,
+	`date_iso` text,
+	`reserve_av_percent` real DEFAULT 0 NOT NULL,
+	`reserve_sv_percent` real DEFAULT 0 NOT NULL,
+	`sort_order` integer DEFAULT 0 NOT NULL,
+	FOREIGN KEY (`project_id`) REFERENCES `projects`(`id`) ON UPDATE no action ON DELETE cascade
+);
+--> statement-breakpoint
+CREATE INDEX `estimate_balances_project_id_idx` ON `estimate_balances` (`project_id`);--> statement-breakpoint
+CREATE TABLE `estimate_groups` (
+	`id` text PRIMARY KEY NOT NULL,
+	`balance_id` text NOT NULL,
+	`cost_group` text DEFAULT '' NOT NULL,
+	`title` text NOT NULL,
+	`editor` text,
+	`sort_order` integer DEFAULT 0 NOT NULL,
+	FOREIGN KEY (`balance_id`) REFERENCES `estimate_balances`(`id`) ON UPDATE no action ON DELETE cascade
+);
+--> statement-breakpoint
+CREATE INDEX `estimate_groups_balance_id_idx` ON `estimate_groups` (`balance_id`);--> statement-breakpoint
+CREATE TABLE `estimate_rows` (
+	`id` text PRIMARY KEY NOT NULL,
+	`group_id` text NOT NULL,
+	`sort_order` integer DEFAULT 0 NOT NULL,
+	`supply` text,
+	`name` text DEFAULT '' NOT NULL,
+	`quantity` real DEFAULT 0 NOT NULL,
+	`unit` text DEFAULT 'piece' NOT NULL,
+	`connection` text,
+	`power_per_unit_w` real DEFAULT 0 NOT NULL,
+	`simultaneity_factor` real DEFAULT 1 NOT NULL,
+	`cos_phi` real DEFAULT 1 NOT NULL,
+	`safety_supply` integer DEFAULT false NOT NULL,
+	`remark` text,
+	FOREIGN KEY (`group_id`) REFERENCES `estimate_groups`(`id`) ON UPDATE no action ON DELETE cascade
+);
+--> statement-breakpoint
+CREATE INDEX `estimate_rows_group_id_idx` ON `estimate_rows` (`group_id`);

src/db/migrations/meta/_journal.json

@@ -71,6 +71,13 @@
       "when": 1790419185882,
       "tag": "0009_buildings",
       "breakpoints": true
+    },
+    {
+      "idx": 10,
+      "version": "6",
+      "when": 1790438092269,
+      "tag": "0010_estimate_balances",
+      "breakpoints": true
     }
   ]
 }

src/db/repositories/estimate-balance-project-command.repository.ts

@@ -0,0 +1,132 @@
+import { eq } from "drizzle-orm";
+import {
+  assertEstimateBalanceDeleteProjectCommand,
+  assertEstimateBalanceInsertProjectCommand,
+  assertEstimateBalanceUpdateProjectCommand,
+  createEstimateBalanceDeleteProjectCommand,
+  createEstimateBalanceInsertProjectCommand,
+  createEstimateBalanceUpdateProjectCommand,
+  estimateBalanceDeleteCommandType,
+  estimateBalanceInsertCommandType,
+  estimateBalanceUpdateCommandType,
+  normalizeEstimateBalanceSnapshot,
+  sameEstimateBalance,
+  type EstimateBalanceProjectCommand,
+} from "../../estimate-balance/domain/estimate-balance-command.model.js";
+import type {
+  EstimateBalanceProjectCommandStore,
+  ExecuteEstimateBalanceCommandInput,
+} from "../../estimate-balance/domain/estimate-balance-project-command.store.js";
+import type { EstimateBalanceSnapshot } from "../../shared/estimate-balance/estimate-balance.js";
+import type { AppDatabase } from "../database-context.js";
+import { estimateBalances } from "../schema/estimate-balances.js";
+import { projects } from "../schema/projects.js";
+import { executeProjectCommandTransaction } from "./project-command-transaction.persistence.js";
+import {
+  deleteEstimateBalance,
+  insertEstimateBalance,
+  readEstimateBalances,
+} from "./estimate-balance.persistence.js";
+
+export class EstimateBalanceProjectCommandRepository
+  implements EstimateBalanceProjectCommandStore
+{
+  constructor(private readonly database: AppDatabase) {}
+
+  execute(input: ExecuteEstimateBalanceCommandInput) {
+    return executeProjectCommandTransaction(this.database, input, (tx) =>
+      this.applyCommand(tx, input.projectId, input.command)
+    );
+  }
+
+  private applyCommand(
+    database: AppDatabase,
+    projectId: string,
+    command: EstimateBalanceProjectCommand
+  ): EstimateBalanceProjectCommand {
+    switch (command.type) {
+      case estimateBalanceInsertCommandType:
+        assertEstimateBalanceInsertProjectCommand(command);
+        return this.insert(database, projectId, command.payload.balance);
+      case estimateBalanceDeleteCommandType:
+        assertEstimateBalanceDeleteProjectCommand(command);
+        return this.delete(database, projectId, command.payload.balance);
+      case estimateBalanceUpdateCommandType:
+        assertEstimateBalanceUpdateProjectCommand(command);
+        return this.update(
+          database,
+          projectId,
+          command.payload.expected,
+          command.payload.target
+        );
+    }
+  }
+
+  private insert(
+    database: AppDatabase,
+    projectId: string,
+    balance: EstimateBalanceSnapshot
+  ) {
+    if (balance.projectId !== projectId) {
+      throw new Error("Estimate-balance snapshot does not belong to project.");
+    }
+    const project = database
+      .select({ id: projects.id })
+      .from(projects)
+      .where(eq(projects.id, projectId))
+      .get();
+    if (!project) {
+      throw new Error("Project does not exist.");
+    }
+    const existing = database
+      .select({ id: estimateBalances.id })
+      .from(estimateBalances)
+      .where(eq(estimateBalances.id, balance.id))
+      .get();
+    if (existing) {
+      throw new Error("Estimate-balance id already exists.");
+    }
+    const normalized = normalizeEstimateBalanceSnapshot(balance);
+    insertEstimateBalance(database, normalized);
+    return createEstimateBalanceDeleteProjectCommand(normalized);
+  }
+
+  private delete(
+    database: AppDatabase,
+    projectId: string,
+    expected: EstimateBalanceSnapshot
+  ) {
+    this.assertPersisted(database, projectId, expected, "deletion");
+    if (deleteEstimateBalance(database, projectId, expected.id) !== 1) {
+      throw new Error("Estimate balance could not be deleted.");
+    }
+    return createEstimateBalanceInsertProjectCommand(expected);
+  }
+
+  private update(
+    database: AppDatabase,
+    projectId: string,
+    expected: EstimateBalanceSnapshot,
+    target: EstimateBalanceSnapshot
+  ) {
+    this.assertPersisted(database, projectId, expected, "update");
+    // Group and row ids stay stable; replacing the whole document keeps the
+    // command exact and its inverse trivially the swapped pair.
+    deleteEstimateBalance(database, projectId, expected.id);
+    const normalized = normalizeEstimateBalanceSnapshot(target);
+    insertEstimateBalance(database, normalized);
+    return createEstimateBalanceUpdateProjectCommand(normalized, expected);
+  }
+
+  private assertPersisted(
+    database: AppDatabase,
+    projectId: string,
+    expected: EstimateBalanceSnapshot,
+    action: string
+  ) {
+    const [persisted] = readEstimateBalances(database, projectId, expected.id);
+    if (!persisted || !sameEstimateBalance(persisted, expected)) {
+      throw new Error(`Estimate balance changed before ${action}.`);
+    }
+  }
+}

src/db/repositories/estimate-balance.persistence.ts

@@ -0,0 +1,121 @@
+import { and, asc, eq, inArray } from "drizzle-orm";
+import type { EstimateBalanceSnapshot } from "../../shared/estimate-balance/estimate-balance.js";
+import type { AppDatabase } from "../database-context.js";
+import {
+  estimateBalances,
+  estimateGroups,
+  estimateRows,
+} from "../schema/estimate-balances.js";
+
+/** Reads complete balance documents of a project, ordered like the UI shows them. */
+export function readEstimateBalances(
+  database: AppDatabase,
+  projectId: string,
+  balanceId?: string
+): EstimateBalanceSnapshot[] {
+  const balances = database
+    .select()
+    .from(estimateBalances)
+    .where(
+      balanceId
+        ? and(
+            eq(estimateBalances.projectId, projectId),
+            eq(estimateBalances.id, balanceId)
+          )
+        : eq(estimateBalances.projectId, projectId)
+    )
+    .orderBy(asc(estimateBalances.sortOrder), asc(estimateBalances.id))
+    .all();
+  if (!balances.length) {
+    return [];
+  }
+  const groups = database
+    .select()
+    .from(estimateGroups)
+    .where(inArray(estimateGroups.balanceId, balances.map((balance) => balance.id)))
+    .orderBy(asc(estimateGroups.sortOrder), asc(estimateGroups.id))
+    .all();
+  const rows = groups.length
+    ? database
+        .select()
+        .from(estimateRows)
+        .where(inArray(estimateRows.groupId, groups.map((group) => group.id)))
+        .orderBy(asc(estimateRows.sortOrder), asc(estimateRows.id))
+        .all()
+    : [];
+  return balances.map((balance) => ({
+    id: balance.id,
+    projectId: balance.projectId,
+    name: balance.name,
+    workStage: balance.workStage,
+    dateIso: balance.dateIso,
+    reserveAvPercent: balance.reserveAvPercent,
+    reserveSvPercent: balance.reserveSvPercent,
+    sortOrder: balance.sortOrder,
+    groups: groups
+      .filter((group) => group.balanceId === balance.id)
+      .map((group) => ({
+        id: group.id,
+        costGroup: group.costGroup,
+        title: group.title,
+        editor: group.editor,
+        sortOrder: group.sortOrder,
+        rows: rows
+          .filter((row) => row.groupId === group.id)
+          .map(({ groupId: _groupId, ...row }) => row),
+      })),
+  }));
+}
+
+/** Writes a complete balance document (the caller removed an older version first). */
+export function insertEstimateBalance(
+  database: AppDatabase,
+  balance: EstimateBalanceSnapshot
+) {
+  database
+    .insert(estimateBalances)
+    .values({
+      id: balance.id,
+      projectId: balance.projectId,
+      name: balance.name,
+      workStage: balance.workStage,
+      dateIso: balance.dateIso,
+      reserveAvPercent: balance.reserveAvPercent,
+      reserveSvPercent: balance.reserveSvPercent,
+      sortOrder: balance.sortOrder,
+    })
+    .run();
+  for (const group of balance.groups) {
+    database
+      .insert(estimateGroups)
+      .values({
+        id: group.id,
+        balanceId: balance.id,
+        costGroup: group.costGroup,
+        title: group.title,
+        editor: group.editor,
+        sortOrder: group.sortOrder,
+      })
+      .run();
+    if (group.rows.length) {
+      database
+        .insert(estimateRows)
+        .values(group.rows.map((row) => ({ ...row, groupId: group.id })))
+        .run();
+    }
+  }
+}
+
+/** Removes a balance with its groups and rows (foreign keys cascade). */
+export function deleteEstimateBalance(
+  database: AppDatabase,
+  projectId: string,
+  balanceId: string
+) {
+  return database
+    .delete(estimateBalances)
+    .where(
+      and(eq(estimateBalances.projectId, projectId), eq(estimateBalances.id, balanceId))
+    )
+    .run().changes;
+}

src/db/repositories/estimate-balance.repository.ts

@@ -0,0 +1,60 @@
+import { asc, eq } from "drizzle-orm";
+import type {
+  DetailedDeviceRowPower,
+  EstimateBalanceSnapshot,
+} from "../../shared/estimate-balance/estimate-balance.js";
+import { calculateRowTotalPower } from "../../domain/calculations/circuit-power-calculation.js";
+import type { AppDatabase } from "../database-context.js";
+import { circuitDeviceRows } from "../schema/circuit-device-rows.js";
+import { circuitLists } from "../schema/circuit-lists.js";
+import { circuits } from "../schema/circuits.js";
+import { estimateBalances } from "../schema/estimate-balances.js";
+import { readEstimateBalances } from "./estimate-balance.persistence.js";
+
+/** Read side of the estimate-balance module; writes go through commands. */
+export class EstimateBalanceRepository {
+  constructor(private readonly database: AppDatabase) {}
+
+  listByProject(projectId: string): EstimateBalanceSnapshot[] {
+    return readEstimateBalances(this.database, projectId);
+  }
+
+  findById(projectId: string, balanceId: string): EstimateBalanceSnapshot | null {
+    return readEstimateBalances(this.database, projectId, balanceId)[0] ?? null;
+  }
+
+  nextSortOrder(projectId: string): number {
+    const rows = this.database
+      .select({ sortOrder: estimateBalances.sortOrder })
+      .from(estimateBalances)
+      .where(eq(estimateBalances.projectId, projectId))
+      .orderBy(asc(estimateBalances.sortOrder))
+      .all();
+    return rows.length ? Math.max(...rows.map((row) => row.sortOrder)) + 1 : 0;
+  }
+
+  /**
+   * Device rows of all circuit lists of the project with their total power
+   * (quantity · power per unit · device GZF, like the circuit tree).
+   */
+  listDetailedDeviceRowPower(projectId: string): DetailedDeviceRowPower[] {
+    return this.database
+      .select({
+        costGroup: circuitDeviceRows.costGroup,
+        quantity: circuitDeviceRows.quantity,
+        powerPerUnit: circuitDeviceRows.powerPerUnit,
+        simultaneityFactor: circuitDeviceRows.simultaneityFactor,
+        cosPhi: circuitDeviceRows.cosPhi,
+      })
+      .from(circuitDeviceRows)
+      .innerJoin(circuits, eq(circuits.id, circuitDeviceRows.circuitId))
+      .innerJoin(circuitLists, eq(circuitLists.id, circuits.circuitListId))
+      .where(eq(circuitLists.projectId, projectId))
+      .all()
+      .map((row) => ({
+        costGroup: row.costGroup,
+        kw: calculateRowTotalPower(row.quantity, row.powerPerUnit, row.simultaneityFactor),
+        cosPhi: row.cosPhi,
+      }));
+  }
+}

src/db/repositories/project-state-restore-command.repository.ts

@@ -3,6 +3,8 @@ import { ProjectStateConflictError } from "../../domain/errors/project-state-con
 import {
   assertProjectStateRestoreCommand,
   createProjectStateRestoreCommand,
+  createProjectTransferRestoreCommand,
+  projectStateRestoreCommandSchemaVersion,
 } from "../../domain/models/project-state-restore-command.model.js";
 import {
   parseProjectStateSnapshot,
@@ -13,6 +15,8 @@ import type {
   ProjectStateRestoreCommandStore,
 } from "../../domain/ports/project-state-restore-command.store.js";
 import type { AppDatabase } from "../database-context.js";
+import { canonicalEstimateBalance } from "../../estimate-balance/domain/estimate-balance-command.model.js";
+import type { EstimateBalanceSnapshot } from "../../shared/estimate-balance/estimate-balance.js";
 import { circuitDeviceRows } from "../schema/circuit-device-rows.js";
 import { circuitLists } from "../schema/circuit-lists.js";
 import { circuitProtectionDevices } from "../schema/circuit-protection-devices.js";
@@ -32,6 +36,11 @@ import { externalImportBatches } from "../schema/external-import-batches.js";
 import { externalModelObjects } from "../schema/external-model-objects.js";
 import { externalModelSources } from "../schema/external-model-sources.js";
 import { externalRoomMappings } from "../schema/external-room-mappings.js";
+import { estimateBalances } from "../schema/estimate-balances.js";
+import {
+  insertEstimateBalance,
+  readEstimateBalances,
+} from "./estimate-balance.persistence.js";
 import { executeProjectCommandTransaction } from "./project-command-transaction.persistence.js";
 import {
   readProjectStateSnapshot,
@@ -66,10 +75,39 @@ export class ProjectStateRestoreCommandRepository
     if (!current) {
       throw new Error("Project not found.");
     }
+    const currentEstimateBalances = readEstimateBalances(tx, input.projectId);
+    const transferCommand =
+      input.command.schemaVersion === projectStateRestoreCommandSchemaVersion
+        ? input.command
+        : null;
     if (
       current.payloadSha256 !==
         input.command.payload.expectedStateSha256 &&
-      !matchesHistoryRestoreTarget(tx, input, current.state)
+      !matchesHistoryRestoreTarget(
+        tx,
+        input,
+        current.state,
+        currentEstimateBalances
+      )
+    ) {
+      throw new ProjectStateConflictError(
+        input.projectId,
+        input.command.payload.expectedStateSha256,
+        current.payloadSha256
+      );
+    }
+    if (
+      transferCommand &&
+      canonicalEstimateBalances(currentEstimateBalances) !==
+        canonicalEstimateBalances(
+          transferCommand.payload.expectedEstimateBalances
+        ) &&
+      !matchesHistoryRestoreTarget(
+        tx,
+        input,
+        current.state,
+        currentEstimateBalances
+      )
     ) {
       throw new ProjectStateConflictError(
         input.projectId,
@@ -82,14 +120,28 @@ export class ProjectStateRestoreCommandRepository
       input.command.payload.targetState
     );
     replaceProjectState(tx, targetState);
+    if (transferCommand) {
+      replaceEstimateBalances(
+        tx,
+        input.projectId,
+        transferCommand.payload.targetEstimateBalances
+      );
+    }
     const persistedTarget = readProjectStateSnapshot(tx, input.projectId);
     if (!persistedTarget) {
       throw new Error("Restored project could not be loaded.");
     }
-    const inverse = createProjectStateRestoreCommand(
-      persistedTarget.payloadSha256,
-      current.state
-    );
+    const inverse = transferCommand
+      ? createProjectTransferRestoreCommand(
+          persistedTarget.payloadSha256,
+          current.state,
+          transferCommand.payload.targetEstimateBalances,
+          currentEstimateBalances
+        )
+      : createProjectStateRestoreCommand(
+          persistedTarget.payloadSha256,
+          current.state
+        );
 
     return inverse;
   }
@@ -98,7 +150,8 @@ export class ProjectStateRestoreCommandRepository
 function matchesHistoryRestoreTarget(
   database: AppDatabase,
   input: ExecuteProjectStateRestoreCommandInput,
-  currentState: ProjectStateSnapshot
+  currentState: ProjectStateSnapshot,
+  currentEstimateBalances: EstimateBalanceSnapshot[]
 ) {
   if (
     (input.source !== "undo" && input.source !== "redo") ||
@@ -122,25 +175,45 @@ function matchesHistoryRestoreTarget(
       input.source === "undo"
         ? changeSet.forwardPayloadJson
         : changeSet.inversePayloadJson;
-    const command = JSON.parse(serialized) as {
-      type?: unknown;
-      payload?: { targetState?: unknown };
-    };
-    if (command.type !== "project.restore-state") {
+    const command = JSON.parse(serialized) as unknown;
+    assertProjectStateRestoreCommand(command);
+    const expectedState = parseProjectStateSnapshot(command.payload.targetState);
+    const stateMatches =
+      canonicalProjectState(expectedState) ===
+      canonicalProjectState(currentState);
+    if (!stateMatches) {
       return false;
     }
-    const expectedState = parseProjectStateSnapshot(
-      command.payload?.targetState
-    );
-    return (
-      canonicalProjectState(expectedState) ===
-      canonicalProjectState(currentState)
-    );
+    return command.schemaVersion !== projectStateRestoreCommandSchemaVersion ||
+      canonicalEstimateBalances(command.payload.targetEstimateBalances) ===
+        canonicalEstimateBalances(currentEstimateBalances);
   } catch {
     return false;
   }
 }
 
+function canonicalEstimateBalances(balances: EstimateBalanceSnapshot[]) {
+  return JSON.stringify(
+    [...balances]
+      .sort((left, right) => left.id.localeCompare(right.id))
+      .map((balance) => canonicalEstimateBalance(balance))
+  );
+}
+
+function replaceEstimateBalances(
+  database: AppDatabase,
+  projectId: string,
+  balances: EstimateBalanceSnapshot[]
+) {
+  database
+    .delete(estimateBalances)
+    .where(eq(estimateBalances.projectId, projectId))
+    .run();
+  for (const balance of balances) {
+    insertEstimateBalance(database, balance);
+  }
+}
+
 function canonicalProjectState(state: ProjectStateSnapshot) {
   return JSON.stringify({
     ...state,

src/db/repositories/project-transfer.repository.ts

@@ -3,9 +3,11 @@ import { eq } from "drizzle-orm";
 import {
   createProjectTransferEnvelope,
   parseProjectTransferEnvelope,
+  remapEstimateBalances,
   remapProjectState,
+  serializeProjectTransferPayload,
 } from "../../domain/models/project-transfer.model.js";
-import { createProjectStateRestoreCommand } from "../../domain/models/project-state-restore-command.model.js";
+import { createProjectTransferRestoreCommand } from "../../domain/models/project-state-restore-command.model.js";
 import type { ProjectTransferStore } from "../../domain/ports/project-transfer.store.js";
 import type { AppDatabase } from "../database-context.js";
 import { circuitDeviceRows } from "../schema/circuit-device-rows.js";
@@ -26,6 +28,10 @@ import { externalImportBatches } from "../schema/external-import-batches.js";
 import { externalModelObjects } from "../schema/external-model-objects.js";
 import { externalModelSources } from "../schema/external-model-sources.js";
 import { externalRoomMappings } from "../schema/external-room-mappings.js";
+import {
+  insertEstimateBalance,
+  readEstimateBalances,
+} from "./estimate-balance.persistence.js";
 import {
   hashProjectStatePayload,
   readProjectStateSnapshot,
@@ -40,10 +46,15 @@ export class ProjectTransferRepository implements ProjectTransferStore {
     if (!snapshot) {
       return null;
     }
+    const estimateBalances = readEstimateBalances(this.database, projectId);
+    const payloadSha256 = hashProjectStatePayload(
+      serializeProjectTransferPayload(snapshot.state, estimateBalances)
+    );
     return createProjectTransferEnvelope(
       new Date().toISOString(),
-      snapshot.payloadSha256,
-      snapshot.state
+      payloadSha256,
+      snapshot.state,
+      estimateBalances
     );
   }
 
@@ -61,10 +72,21 @@ export class ProjectTransferRepository implements ProjectTransferStore {
             projectId,
             () => crypto.randomUUID()
           );
+    const currentEstimateBalances = readEstimateBalances(this.database, projectId);
+    const targetEstimateBalances =
+      transfer.projectState.project.id === projectId
+        ? transfer.estimateBalances
+        : remapEstimateBalances(
+            transfer.estimateBalances,
+            projectId,
+            () => crypto.randomUUID()
+          );
     return {
-      command: createProjectStateRestoreCommand(
+      command: createProjectTransferRestoreCommand(
         current.payloadSha256,
-        targetState
+        targetState,
+        currentEstimateBalances,
+        targetEstimateBalances
       ),
     };
   }
@@ -78,20 +100,39 @@ export class ProjectTransferRepository implements ProjectTransferStore {
       () => crypto.randomUUID(),
       `${transfer.projectState.project.name} (Kopie)`
     );
-    this.database.transaction((tx) => insertProjectState(tx, state));
+    const estimateBalances = remapEstimateBalances(
+      transfer.estimateBalances,
+      projectId,
+      () => crypto.randomUUID()
+    );
+    this.database.transaction((tx) => {
+      insertProjectState(tx, state);
+      for (const balance of estimateBalances) {
+        insertEstimateBalance(tx, balance);
+      }
+    });
     return { projectId, name: state.project.name };
   }
 
   private parseVerified(value: unknown) {
-    const rawPayloadSha256 =
-      isPlainObject(value) &&
-      isPlainObject(value.projectState)
-        ? hashProjectStatePayload(JSON.stringify(value.projectState))
-        : null;
+    const isLegacy = isPlainObject(value) && value.formatVersion === 1;
+    const rawPayloadSha256 = isPlainObject(value) && isPlainObject(value.projectState)
+      ? hashProjectStatePayload(
+          isLegacy
+            ? JSON.stringify(value.projectState)
+            : JSON.stringify({
+                projectState: value.projectState,
+                estimateBalances: value.estimateBalances,
+              })
+        )
+      : null;
     const transfer = parseProjectTransferEnvelope(value);
-    const payloadJson = serializeProjectStateSnapshot(
-      transfer.projectState
-    );
+    const payloadJson = isLegacy
+      ? serializeProjectStateSnapshot(transfer.projectState)
+      : serializeProjectTransferPayload(
+          transfer.projectState,
+          transfer.estimateBalances
+        );
     if (
       hashProjectStatePayload(payloadJson) !== transfer.payloadSha256 &&
       rawPayloadSha256 !== transfer.payloadSha256

src/db/schema/estimate-balances.ts

@@ -0,0 +1,60 @@
+import { index, integer, real, sqliteTable, text } from "drizzle-orm/sqlite-core";
+import { projects } from "./projects.js";
+
+// Grobe Leistungsbilanz (LPH 2/3): a separate module without links into the
+// circuit structure. See docs/estimate-balance.md.
+export const estimateBalances = sqliteTable(
+  "estimate_balances",
+  {
+    id: text("id").primaryKey(),
+    projectId: text("project_id")
+      .notNull()
+      .references(() => projects.id, { onDelete: "cascade" }),
+    name: text("name").notNull(),
+    workStage: text("work_stage"),
+    dateIso: text("date_iso"),
+    reserveAvPercent: real("reserve_av_percent").notNull().default(0),
+    reserveSvPercent: real("reserve_sv_percent").notNull().default(0),
+    sortOrder: integer("sort_order").notNull().default(0),
+  },
+  (table) => [index("estimate_balances_project_id_idx").on(table.projectId)]
+);
+
+export const estimateGroups = sqliteTable(
+  "estimate_groups",
+  {
+    id: text("id").primaryKey(),
+    balanceId: text("balance_id")
+      .notNull()
+      .references(() => estimateBalances.id, { onDelete: "cascade" }),
+    costGroup: text("cost_group").notNull().default(""),
+    title: text("title").notNull(),
+    editor: text("editor"),
+    sortOrder: integer("sort_order").notNull().default(0),
+  },
+  (table) => [index("estimate_groups_balance_id_idx").on(table.balanceId)]
+);
+
+export const estimateRows = sqliteTable(
+  "estimate_rows",
+  {
+    id: text("id").primaryKey(),
+    groupId: text("group_id")
+      .notNull()
+      .references(() => estimateGroups.id, { onDelete: "cascade" }),
+    sortOrder: integer("sort_order").notNull().default(0),
+    supply: text("supply"),
+    name: text("name").notNull().default(""),
+    quantity: real("quantity").notNull().default(0),
+    unit: text("unit", { enum: ["piece", "area"] }).notNull().default("piece"),
+    connection: text("connection", { enum: ["fixed", "socket"] }),
+    powerPerUnitW: real("power_per_unit_w").notNull().default(0),
+    simultaneityFactor: real("simultaneity_factor").notNull().default(1),
+    cosPhi: real("cos_phi").notNull().default(1),
+    safetySupply: integer("safety_supply", { mode: "boolean" })
+      .notNull()
+      .default(false),
+    remark: text("remark"),
+  },
+  (table) => [index("estimate_rows_group_id_idx").on(table.groupId)]
+);

src/domain/models/project-state-restore-command.model.ts

@@ -3,32 +3,80 @@ import {
   type ProjectStateSnapshot,
 } from "./project-state-snapshot.model.js";
 import type { SerializedProjectCommand } from "./project-command.model.js";
+import {
+  parseEstimateBalanceSnapshot,
+} from "../../estimate-balance/domain/estimate-balance-command.model.js";
+import type { EstimateBalanceSnapshot } from "../../shared/estimate-balance/estimate-balance.js";
 
 export const projectStateRestoreCommandType = "project.restore-state";
-export const projectStateRestoreCommandSchemaVersion = 1 as const;
+export const projectStateRestoreCommandSchemaVersion = 2 as const;
+const snapshotRestoreCommandSchemaVersion = 1 as const;
 
 export interface ProjectStateRestoreCommandPayload {
   expectedStateSha256: string;
   targetState: ProjectStateSnapshot;
 }
 
-export type ProjectStateRestoreCommand = SerializedProjectCommand<
+export type SnapshotProjectStateRestoreCommand = SerializedProjectCommand<
   ProjectStateRestoreCommandPayload
+> & {
+  schemaVersion: typeof snapshotRestoreCommandSchemaVersion;
+  type: typeof projectStateRestoreCommandType;
+};
+
+export interface ProjectTransferRestoreCommandPayload
+  extends ProjectStateRestoreCommandPayload {
+  expectedEstimateBalances: EstimateBalanceSnapshot[];
+  targetEstimateBalances: EstimateBalanceSnapshot[];
+}
+
+export type ProjectTransferRestoreCommand = SerializedProjectCommand<
+  ProjectTransferRestoreCommandPayload
 > & {
   schemaVersion: typeof projectStateRestoreCommandSchemaVersion;
   type: typeof projectStateRestoreCommandType;
 };
 
+export type ProjectStateRestoreCommand =
+  | SnapshotProjectStateRestoreCommand
+  | ProjectTransferRestoreCommand;
+
 export function createProjectStateRestoreCommand(
   expectedStateSha256: string,
   targetState: ProjectStateSnapshot
 ): ProjectStateRestoreCommand {
-  const command: ProjectStateRestoreCommand = {
+  const command: SnapshotProjectStateRestoreCommand = {
+    schemaVersion: snapshotRestoreCommandSchemaVersion,
+    type: projectStateRestoreCommandType,
+    payload: {
+      expectedStateSha256,
+      targetState: parseProjectStateSnapshot(targetState),
+    },
+  };
+  assertProjectStateRestoreCommand(command);
+  return command;
+}
+
+export function createProjectTransferRestoreCommand(
+  expectedStateSha256: string,
+  targetState: ProjectStateSnapshot,
+  expectedEstimateBalances: EstimateBalanceSnapshot[],
+  targetEstimateBalances: EstimateBalanceSnapshot[]
+): ProjectTransferRestoreCommand {
+  const command: ProjectTransferRestoreCommand = {
     schemaVersion: projectStateRestoreCommandSchemaVersion,
     type: projectStateRestoreCommandType,
     payload: {
       expectedStateSha256,
       targetState: parseProjectStateSnapshot(targetState),
+      expectedEstimateBalances: parseEstimateBalances(
+        expectedEstimateBalances,
+        targetState.project.id
+      ),
+      targetEstimateBalances: parseEstimateBalances(
+        targetEstimateBalances,
+        targetState.project.id
+      ),
     },
   };
   assertProjectStateRestoreCommand(command);
@@ -42,10 +90,7 @@ export function assertProjectStateRestoreCommand(
     throw new Error("Project state restore command must be an object.");
   }
   const command = value as Partial<ProjectStateRestoreCommand>;
-  if (
-    command.type !== projectStateRestoreCommandType ||
-    command.schemaVersion !== projectStateRestoreCommandSchemaVersion
-  ) {
+  if (command.type !== projectStateRestoreCommandType) {
     throw new Error("Unsupported project state restore command.");
   }
   if (!command.payload || typeof command.payload !== "object") {
@@ -58,5 +103,43 @@ export function assertProjectStateRestoreCommand(
   ) {
     throw new Error("Expected project state checksum is invalid.");
   }
-  parseProjectStateSnapshot(payload.targetState);
+  const targetState = parseProjectStateSnapshot(payload.targetState);
+  if (command.schemaVersion === snapshotRestoreCommandSchemaVersion) {
+    if (Object.keys(payload).length !== 2) {
+      throw new Error("Snapshot restore payload contains unknown fields.");
+    }
+    return;
+  }
+  if (command.schemaVersion !== projectStateRestoreCommandSchemaVersion) {
+    throw new Error("Unsupported project state restore command.");
+  }
+  const transferPayload = payload as Partial<ProjectTransferRestoreCommandPayload>;
+  parseEstimateBalances(
+    transferPayload.expectedEstimateBalances,
+    targetState.project.id
+  );
+  parseEstimateBalances(
+    transferPayload.targetEstimateBalances,
+    targetState.project.id
+  );
+  if (Object.keys(payload).length !== 4) {
+    throw new Error("Project transfer restore payload contains unknown fields.");
+  }
+}
+
+function parseEstimateBalances(
+  value: unknown,
+  projectId: string
+): EstimateBalanceSnapshot[] {
+  if (!Array.isArray(value)) {
+    throw new Error("Project transfer estimate balances must be an array.");
+  }
+  const balances = value.map(parseEstimateBalanceSnapshot);
+  if (balances.some((balance) => balance.projectId !== projectId)) {
+    throw new Error("Project transfer estimate balance belongs to another project.");
+  }
+  if (new Set(balances.map((balance) => balance.id)).size !== balances.length) {
+    throw new Error("Project transfer contains duplicate estimate balances.");
+  }
+  return balances;
 }

src/domain/models/project-transfer.model.ts

@@ -3,9 +3,12 @@ import {
   projectStateSnapshotSchemaVersion,
   type ProjectStateSnapshot,
 } from "./project-state-snapshot.model.js";
+import { parseEstimateBalanceSnapshot } from "../../estimate-balance/domain/estimate-balance-command.model.js";
+import type { EstimateBalanceSnapshot } from "../../shared/estimate-balance/estimate-balance.js";
 
 export const projectTransferFormat = "leistungsbilanz.project" as const;
-export const projectTransferFormatVersion = 1 as const;
+export const projectTransferFormatVersion = 2 as const;
+const legacyProjectTransferFormatVersion = 1 as const;
 
 export interface ProjectTransferEnvelope {
   format: typeof projectTransferFormat;
@@ -13,12 +16,14 @@ export interface ProjectTransferEnvelope {
   exportedAtIso: string;
   payloadSha256: string;
   projectState: ProjectStateSnapshot;
+  estimateBalances: EstimateBalanceSnapshot[];
 }
 
 export function createProjectTransferEnvelope(
   exportedAtIso: string,
   payloadSha256: string,
-  projectState: ProjectStateSnapshot
+  projectState: ProjectStateSnapshot,
+  estimateBalances: EstimateBalanceSnapshot[]
 ): ProjectTransferEnvelope {
   return parseProjectTransferEnvelope({
     format: projectTransferFormat,
@@ -26,6 +31,7 @@ export function createProjectTransferEnvelope(
     exportedAtIso,
     payloadSha256,
     projectState,
+    estimateBalances,
   });
 }
 
@@ -37,7 +43,8 @@ export function parseProjectTransferEnvelope(
   }
   if (
     value.format !== projectTransferFormat ||
-    value.formatVersion !== projectTransferFormatVersion
+    (value.formatVersion !== legacyProjectTransferFormatVersion &&
+      value.formatVersion !== projectTransferFormatVersion)
   ) {
     throw new Error("Project transfer format is not supported.");
   }
@@ -57,7 +64,13 @@ export function parseProjectTransferEnvelope(
   if (projectState.schemaVersion !== projectStateSnapshotSchemaVersion) {
     throw new Error("Project transfer snapshot version is not supported.");
   }
-  if (Object.keys(value).length !== 5) {
+  const estimateBalances =
+    value.formatVersion === legacyProjectTransferFormatVersion
+      ? []
+      : parseTransferEstimateBalances(value.estimateBalances, projectState.project.id);
+  const expectedFieldCount =
+    value.formatVersion === legacyProjectTransferFormatVersion ? 5 : 6;
+  if (Object.keys(value).length !== expectedFieldCount) {
     throw new Error("Project transfer file contains unknown fields.");
   }
   return {
@@ -66,9 +79,43 @@ export function parseProjectTransferEnvelope(
     exportedAtIso: value.exportedAtIso,
     payloadSha256: value.payloadSha256,
     projectState,
+    estimateBalances,
   };
 }
 
+export function serializeProjectTransferPayload(
+  projectState: ProjectStateSnapshot,
+  estimateBalances: EstimateBalanceSnapshot[]
+) {
+  const parsedState = parseProjectStateSnapshot(projectState);
+  return JSON.stringify({
+    projectState: parsedState,
+    estimateBalances: parseTransferEstimateBalances(
+      estimateBalances,
+      parsedState.project.id
+    ),
+  });
+}
+
+export function remapEstimateBalances(
+  source: EstimateBalanceSnapshot[],
+  targetProjectId: string,
+  createId: () => string
+): EstimateBalanceSnapshot[] {
+  return source.map((balance) =>
+    parseEstimateBalanceSnapshot({
+      ...balance,
+      id: createId(),
+      projectId: targetProjectId,
+      groups: balance.groups.map((group) => ({
+        ...group,
+        id: createId(),
+        rows: group.rows.map((row) => ({ ...row, id: createId() })),
+      })),
+    })
+  );
+}
+
 export function remapProjectState(
   source: ProjectStateSnapshot,
   targetProjectId: string,
@@ -282,6 +329,37 @@ function requiredId(ids: ReadonlyMap<string, string>, sourceId: string) {
   return targetId;
 }
 
+function parseTransferEstimateBalances(
+  value: unknown,
+  projectId: string
+): EstimateBalanceSnapshot[] {
+  if (!Array.isArray(value)) {
+    throw new Error("Project transfer estimate balances must be an array.");
+  }
+  const balances = value.map(parseEstimateBalanceSnapshot);
+  if (balances.some((balance) => balance.projectId !== projectId)) {
+    throw new Error("Project transfer estimate balance belongs to another project.");
+  }
+  assertUniqueIds(balances.map((balance) => balance.id), "estimate balance");
+  assertUniqueIds(
+    balances.flatMap((balance) => balance.groups.map((group) => group.id)),
+    "estimate group"
+  );
+  assertUniqueIds(
+    balances.flatMap((balance) =>
+      balance.groups.flatMap((group) => group.rows.map((row) => row.id))
+    ),
+    "estimate row"
+  );
+  return balances;
+}
+
+function assertUniqueIds(ids: string[], label: string) {
+  if (new Set(ids).size !== ids.length) {
+    throw new Error(`Project transfer contains a duplicate ${label} id.`);
+  }
+}
+
 function isPlainObject(value: unknown): value is Record<string, unknown> {
   return value !== null && typeof value === "object" && !Array.isArray(value);
 }

src/domain/services/project-command.service.ts

@@ -194,6 +194,15 @@ import {
   externalObjectDeleteCreatedCircuitCommandType,
 } from "../models/external-object-new-circuit-project-command.model.js";
 import type { ExternalObjectNewCircuitProjectCommandStore } from "../ports/external-object-new-circuit-project-command.store.js";
+import {
+  assertEstimateBalanceDeleteProjectCommand,
+  assertEstimateBalanceInsertProjectCommand,
+  assertEstimateBalanceUpdateProjectCommand,
+  estimateBalanceDeleteCommandType,
+  estimateBalanceInsertCommandType,
+  estimateBalanceUpdateCommandType,
+} from "../../estimate-balance/domain/estimate-balance-command.model.js";
+import type { EstimateBalanceProjectCommandStore } from "../../estimate-balance/domain/estimate-balance-project-command.store.js";
 
 interface DispatchProjectCommandInput {
   projectId: string;
@@ -233,7 +242,8 @@ export class ProjectCommandService implements ProjectCommandExecutor {
     private readonly externalInitialImportStore?: ExternalInitialImportProjectCommandStore,
     private readonly externalObjectRowAssignmentStore?: ExternalObjectRowAssignmentProjectCommandStore,
     private readonly externalObjectNewRowStore?: ExternalObjectNewRowProjectCommandStore,
-    private readonly externalObjectNewCircuitStore?: ExternalObjectNewCircuitProjectCommandStore
+    private readonly externalObjectNewCircuitStore?: ExternalObjectNewCircuitProjectCommandStore,
+    private readonly estimateBalanceStore?: EstimateBalanceProjectCommandStore
   ) {}
 
   executeUser(
@@ -654,6 +664,24 @@ export class ProjectCommandService implements ProjectCommandExecutor {
           command: input.command,
         }).revision;
       }
+      case estimateBalanceInsertCommandType:
+      case estimateBalanceDeleteCommandType:
+      case estimateBalanceUpdateCommandType: {
+        if (input.command.type === estimateBalanceInsertCommandType) {
+          assertEstimateBalanceInsertProjectCommand(input.command);
+        } else if (input.command.type === estimateBalanceDeleteCommandType) {
+          assertEstimateBalanceDeleteProjectCommand(input.command);
+        } else {
+          assertEstimateBalanceUpdateProjectCommand(input.command);
+        }
+        if (!this.estimateBalanceStore) {
+          throw new Error("Estimate-balance store is not available.");
+        }
+        return this.estimateBalanceStore.execute({
+          ...input,
+          command: input.command,
+        }).revision;
+      }
       case projectStateRestoreCommandType: {
         assertProjectStateRestoreCommand(input.command);
         return this.projectStateRestoreStore.execute({

src/estimate-balance/api/estimate-balance-request.schemas.ts

@@ -0,0 +1,33 @@
+import { z } from "zod";
+import { expectedProjectRevisionSchema } from "../../shared/validation/project-command.schemas.js";
+
+export const createEstimateBalanceRequestSchema = z
+  .object({
+    expectedRevision: expectedProjectRevisionSchema,
+    name: z.string().trim().min(1).max(200),
+    workStage: z.string().trim().max(50).nullable().optional(),
+    dateIso: z
+      .string()
+      .regex(/^\d{4}-\d{2}-\d{2}$/)
+      .nullable()
+      .optional(),
+    template: z.enum(["kg400", "empty", "copy"]),
+    copyFromBalanceId: z.string().trim().min(1).optional(),
+  })
+  .strict()
+  .refine((input) => input.template !== "copy" || Boolean(input.copyFromBalanceId), {
+    message: "copyFromBalanceId is required for template copy",
+    path: ["copyFromBalanceId"],
+  });
+
+export const updateEstimateBalanceRequestSchema = z
+  .object({
+    expectedRevision: expectedProjectRevisionSchema,
+    // Validated in detail by parseEstimateBalanceSnapshot.
+    balance: z.unknown(),
+  })
+  .strict();
+
+export const deleteEstimateBalanceRequestSchema = z
+  .object({ expectedRevision: expectedProjectRevisionSchema })
+  .strict();

src/estimate-balance/domain/estimate-balance-command.model.ts

@@ -0,0 +1,318 @@
+import crypto from "node:crypto";
+import { z } from "zod";
+import type { SerializedProjectCommand } from "../../domain/models/project-command.model.js";
+import {
+  estimateDefaultGroups,
+  type EstimateBalanceSnapshot,
+  type EstimateGroupSnapshot,
+} from "../../shared/estimate-balance/estimate-balance.js";
+
+export const estimateBalanceInsertCommandType = "estimate-balance.insert" as const;
+export const estimateBalanceDeleteCommandType = "estimate-balance.delete" as const;
+export const estimateBalanceUpdateCommandType = "estimate-balance.update" as const;
+export const estimateBalanceCommandSchemaVersion = 1 as const;
+
+const idSchema = z.string().trim().min(1).max(100);
+const trimmed = (max: number) =>
+  z.string().max(max).refine((value) => value === value.trim(), {
+    message: "must be trimmed",
+  });
+const nullableText = (max: number) =>
+  trimmed(max)
+    .refine((value) => value.length > 0, { message: "use null instead of empty" })
+    .nullable();
+const finite = z.number().finite();
+
+export const estimateRowSnapshotSchema = z
+  .object({
+    id: idSchema,
+    sortOrder: z.number().int().min(0),
+    supply: nullableText(50),
+    name: trimmed(200),
+    quantity: finite.min(0),
+    unit: z.enum(["piece", "area"]),
+    connection: z.enum(["fixed", "socket"]).nullable(),
+    powerPerUnitW: finite.min(0),
+    simultaneityFactor: finite.min(0).max(1),
+    cosPhi: finite.gt(0).max(1),
+    safetySupply: z.boolean(),
+    remark: nullableText(500),
+  })
+  .strict();
+
+export const estimateGroupSnapshotSchema = z
+  .object({
+    id: idSchema,
+    costGroup: trimmed(20),
+    title: trimmed(200).refine((value) => value.length > 0, {
+      message: "title must not be empty",
+    }),
+    editor: nullableText(100),
+    sortOrder: z.number().int().min(0),
+    rows: z.array(estimateRowSnapshotSchema).max(1000),
+  })
+  .strict();
+
+export const estimateBalanceSnapshotSchema = z
+  .object({
+    id: idSchema,
+    projectId: idSchema,
+    name: trimmed(200).refine((value) => value.length > 0, {
+      message: "name must not be empty",
+    }),
+    workStage: nullableText(50),
+    dateIso: z
+      .string()
+      .regex(/^\d{4}-\d{2}-\d{2}$/)
+      .refine((value) => !Number.isNaN(Date.parse(`${value}T00:00:00Z`)), {
+        message: "invalid date",
+      })
+      .nullable(),
+    reserveAvPercent: finite.min(0).max(100),
+    reserveSvPercent: finite.min(0).max(100),
+    sortOrder: z.number().int().min(0),
+    groups: z.array(estimateGroupSnapshotSchema).max(200),
+  })
+  .strict()
+  .superRefine((balance, context) => {
+    const ids = new Set<string>();
+    for (const group of balance.groups) {
+      for (const id of [group.id, ...group.rows.map((row) => row.id)]) {
+        if (ids.has(id)) {
+          context.addIssue({
+            code: "custom",
+            message: `duplicate id ${id}`,
+            path: ["groups"],
+          });
+        }
+        ids.add(id);
+      }
+    }
+  });
+
+export interface EstimateBalanceInsertProjectCommand
+  extends SerializedProjectCommand<{ balance: EstimateBalanceSnapshot }> {
+  schemaVersion: typeof estimateBalanceCommandSchemaVersion;
+  type: typeof estimateBalanceInsertCommandType;
+}
+
+export interface EstimateBalanceDeleteProjectCommand
+  extends SerializedProjectCommand<{ balance: EstimateBalanceSnapshot }> {
+  schemaVersion: typeof estimateBalanceCommandSchemaVersion;
+  type: typeof estimateBalanceDeleteCommandType;
+}
+
+export interface EstimateBalanceUpdateProjectCommand
+  extends SerializedProjectCommand<{
+    expected: EstimateBalanceSnapshot;
+    target: EstimateBalanceSnapshot;
+  }> {
+  schemaVersion: typeof estimateBalanceCommandSchemaVersion;
+  type: typeof estimateBalanceUpdateCommandType;
+}
+
+export type EstimateBalanceProjectCommand =
+  | EstimateBalanceInsertProjectCommand
+  | EstimateBalanceDeleteProjectCommand
+  | EstimateBalanceUpdateProjectCommand;
+
+/** Parses and normalizes a snapshot (sort orders of groups and rows follow the array order). */
+export function parseEstimateBalanceSnapshot(value: unknown): EstimateBalanceSnapshot {
+  const parsed = estimateBalanceSnapshotSchema.parse(value);
+  return normalizeEstimateBalanceSnapshot(parsed);
+}
+
+export function normalizeEstimateBalanceSnapshot(
+  balance: EstimateBalanceSnapshot
+): EstimateBalanceSnapshot {
+  return {
+    ...balance,
+    groups: balance.groups.map((group, groupIndex) => ({
+      ...group,
+      sortOrder: groupIndex,
+      rows: group.rows.map((row, rowIndex) => ({ ...row, sortOrder: rowIndex })),
+    })),
+  };
+}
+
+/** Stable JSON for exact equality checks of two snapshots. */
+export function canonicalEstimateBalance(balance: EstimateBalanceSnapshot): string {
+  const normalized = normalizeEstimateBalanceSnapshot(balance);
+  return JSON.stringify({
+    id: normalized.id,
+    projectId: normalized.projectId,
+    name: normalized.name,
+    workStage: normalized.workStage,
+    dateIso: normalized.dateIso,
+    reserveAvPercent: normalized.reserveAvPercent,
+    reserveSvPercent: normalized.reserveSvPercent,
+    sortOrder: normalized.sortOrder,
+    groups: normalized.groups.map((group) => ({
+      id: group.id,
+      costGroup: group.costGroup,
+      title: group.title,
+      editor: group.editor,
+      sortOrder: group.sortOrder,
+      rows: group.rows.map((row) => ({
+        id: row.id,
+        sortOrder: row.sortOrder,
+        supply: row.supply,
+        name: row.name,
+        quantity: row.quantity,
+        unit: row.unit,
+        connection: row.connection,
+        powerPerUnitW: row.powerPerUnitW,
+        simultaneityFactor: row.simultaneityFactor,
+        cosPhi: row.cosPhi,
+        safetySupply: row.safetySupply,
+        remark: row.remark,
+      })),
+    })),
+  });
+}
+
+export function sameEstimateBalance(
+  left: EstimateBalanceSnapshot,
+  right: EstimateBalanceSnapshot
+): boolean {
+  return canonicalEstimateBalance(left) === canonicalEstimateBalance(right);
+}
+
+export function createEstimateBalanceSnapshot(input: {
+  projectId: string;
+  name: string;
+  workStage: string | null;
+  dateIso: string | null;
+  sortOrder: number;
+  template: "kg400" | "empty" | { copyFrom: EstimateBalanceSnapshot };
+  createId?: () => string;
+}): EstimateBalanceSnapshot {
+  const createId = input.createId ?? (() => crypto.randomUUID());
+  let groups: EstimateGroupSnapshot[] = [];
+  let reserveAvPercent = 10;
+  let reserveSvPercent = 0;
+  if (input.template === "kg400") {
+    groups = estimateDefaultGroups.map((group, index) => ({
+      id: createId(),
+      costGroup: group.costGroup,
+      title: group.title,
+      editor: null,
+      sortOrder: index,
+      rows: [],
+    }));
+  } else if (input.template !== "empty") {
+    const source = input.template.copyFrom;
+    reserveAvPercent = source.reserveAvPercent;
+    reserveSvPercent = source.reserveSvPercent;
+    groups = source.groups.map((group) => ({
+      ...group,
+      id: createId(),
+      rows: group.rows.map((row) => ({ ...row, id: createId() })),
+    }));
+  }
+  return parseEstimateBalanceSnapshot({
+    id: createId(),
+    projectId: input.projectId,
+    name: input.name.trim(),
+    workStage: input.workStage?.trim() || null,
+    dateIso: input.dateIso || null,
+    reserveAvPercent,
+    reserveSvPercent,
+    sortOrder: input.sortOrder,
+    groups,
+  });
+}
+
+export function createEstimateBalanceInsertProjectCommand(
+  balance: EstimateBalanceSnapshot
+): EstimateBalanceInsertProjectCommand {
+  return {
+    schemaVersion: estimateBalanceCommandSchemaVersion,
+    type: estimateBalanceInsertCommandType,
+    payload: { balance: parseEstimateBalanceSnapshot(balance) },
+  };
+}
+
+export function createEstimateBalanceDeleteProjectCommand(
+  balance: EstimateBalanceSnapshot
+): EstimateBalanceDeleteProjectCommand {
+  return {
+    schemaVersion: estimateBalanceCommandSchemaVersion,
+    type: estimateBalanceDeleteCommandType,
+    payload: { balance: parseEstimateBalanceSnapshot(balance) },
+  };
+}
+
+export function createEstimateBalanceUpdateProjectCommand(
+  expected: EstimateBalanceSnapshot,
+  target: EstimateBalanceSnapshot
+): EstimateBalanceUpdateProjectCommand {
+  const payload = {
+    expected: parseEstimateBalanceSnapshot(expected),
+    target: parseEstimateBalanceSnapshot(target),
+  };
+  assertMatchingUpdate(payload.expected, payload.target);
+  return {
+    schemaVersion: estimateBalanceCommandSchemaVersion,
+    type: estimateBalanceUpdateCommandType,
+    payload,
+  };
+}
+
+function assertMatchingUpdate(
+  expected: EstimateBalanceSnapshot,
+  target: EstimateBalanceSnapshot
+) {
+  if (expected.id !== target.id || expected.projectId !== target.projectId) {
+    throw new Error("Estimate-balance update must keep id and project.");
+  }
+  if (sameEstimateBalance(expected, target)) {
+    throw new Error("Estimate-balance update must change the balance.");
+  }
+}
+
+function assertCommandShape(
+  command: SerializedProjectCommand<unknown>,
+  type: string,
+  keys: string[]
+): Record<string, unknown> {
+  const payload = command.payload;
+  if (
+    command.schemaVersion !== estimateBalanceCommandSchemaVersion ||
+    command.type !== type ||
+    payload === null ||
+    typeof payload !== "object" ||
+    Array.isArray(payload) ||
+    Object.keys(payload).sort().join(",") !== [...keys].sort().join(",")
+  ) {
+    throw new Error("Unsupported estimate-balance command.");
+  }
+  return payload as Record<string, unknown>;
+}
+
+export function assertEstimateBalanceInsertProjectCommand(
+  command: SerializedProjectCommand<unknown>
+): asserts command is EstimateBalanceInsertProjectCommand {
+  const payload = assertCommandShape(command, estimateBalanceInsertCommandType, ["balance"]);
+  parseEstimateBalanceSnapshot(payload.balance);
+}
+
+export function assertEstimateBalanceDeleteProjectCommand(
+  command: SerializedProjectCommand<unknown>
+): asserts command is EstimateBalanceDeleteProjectCommand {
+  const payload = assertCommandShape(command, estimateBalanceDeleteCommandType, ["balance"]);
+  parseEstimateBalanceSnapshot(payload.balance);
+}
+
+export function assertEstimateBalanceUpdateProjectCommand(
+  command: SerializedProjectCommand<unknown>
+): asserts command is EstimateBalanceUpdateProjectCommand {
+  const payload = assertCommandShape(command, estimateBalanceUpdateCommandType, [
+    "expected",
+    "target",
+  ]);
+  assertMatchingUpdate(
+    parseEstimateBalanceSnapshot(payload.expected),
+    parseEstimateBalanceSnapshot(payload.target)
+  );
+}

src/estimate-balance/domain/estimate-balance-project-command.store.ts

@@ -0,0 +1,24 @@
+import type {
+  AppendedProjectRevision,
+  ProjectRevisionSource,
+} from "../../domain/ports/project-revision.store.js";
+import type { EstimateBalanceProjectCommand } from "./estimate-balance-command.model.js";
+
+export interface ExecuteEstimateBalanceCommandInput {
+  projectId: string;
+  expectedRevision: number;
+  source: ProjectRevisionSource;
+  description?: string;
+  actorId?: string;
+  historyTargetChangeSetId?: string;
+  command: EstimateBalanceProjectCommand;
+}
+
+export interface ExecutedEstimateBalanceCommand {
+  revision: AppendedProjectRevision;
+  inverse: EstimateBalanceProjectCommand;
+}
+
+export interface EstimateBalanceProjectCommandStore {
+  execute(input: ExecuteEstimateBalanceCommandInput): ExecutedEstimateBalanceCommand;
+}

src/frontend/components/Sidebar.tsx

@@ -17,6 +17,7 @@ const PROJECT_SECTIONS = [
 // Separate project sub-routes (/projects/[id]/<segment>).
 const PROJECT_ROUTES = [
   { segment: "struktur", label: "Gebäudestruktur", icon: "▥" },
+  { segment: "grobbilanz", label: "Grobe Leistungsbilanz", icon: "Σ" },
 ] as const;
 
 // Matches the project overview and all of its sub-routes (group 2 = rest).

src/frontend/estimate-balance/estimate-balance-create-modal.tsx

@@ -0,0 +1,162 @@
+"use client";
+
+import { type FormEvent, useState } from "react";
+import { FormModal } from "../components/form-modal";
+import type {
+  CreateEstimateBalanceInput,
+  EstimateBalanceDto,
+  EstimateBalanceTemplate,
+} from "../types";
+import { estimateTextLimits } from "./estimate-balance-document";
+import { getTodayIsoDate } from "./estimate-balance-format";
+
+export interface EstimateBalanceCreateDefaults {
+  name?: string;
+  workStage?: string | null;
+  template?: EstimateBalanceTemplate;
+  copyFromBalanceId?: string;
+}
+
+interface EstimateBalanceCreateModalProps {
+  balances: EstimateBalanceDto[];
+  defaults: EstimateBalanceCreateDefaults;
+  isSaving: boolean;
+  onClose: () => void;
+  onCreate: (input: CreateEstimateBalanceInput) => void;
+}
+
+/** "Neuer Stand": name, LPH, date and the starting content. */
+export function EstimateBalanceCreateModal({
+  balances,
+  defaults,
+  isSaving,
+  onClose,
+  onCreate,
+}: EstimateBalanceCreateModalProps) {
+  const [name, setName] = useState(defaults.name ?? "");
+  const [workStage, setWorkStage] = useState(defaults.workStage ?? "");
+  const [dateIso, setDateIso] = useState(getTodayIsoDate());
+  const [template, setTemplate] = useState<EstimateBalanceTemplate>(
+    defaults.template ?? "kg400"
+  );
+  const [copyFromBalanceId, setCopyFromBalanceId] = useState(
+    defaults.copyFromBalanceId ?? balances[0]?.id ?? ""
+  );
+  const isCopyInvalid = template === "copy" && !copyFromBalanceId;
+
+  function handleSubmit(event: FormEvent<HTMLFormElement>) {
+    event.preventDefault();
+    if (!name.trim() || isCopyInvalid) {
+      return;
+    }
+    onCreate({
+      name: name.trim(),
+      workStage: workStage.trim() || null,
+      dateIso: dateIso || null,
+      template,
+      ...(template === "copy" ? { copyFromBalanceId } : {}),
+    });
+  }
+
+  return (
+    <FormModal
+      isSaving={isSaving}
+      onClose={onClose}
+      onSubmit={handleSubmit}
+      submitDisabled={!name.trim() || isCopyInvalid}
+      submitLabel="Stand anlegen"
+      title="Neuer Stand"
+    >
+      <div className="row g-3">
+        <div className="col-12 col-md-6">
+          <label className="form-label" htmlFor="estimate-create-name">
+            Bezeichnung
+          </label>
+          <input
+            autoFocus
+            className="form-control"
+            id="estimate-create-name"
+            maxLength={estimateTextLimits.balanceName}
+            onChange={(event) => setName(event.target.value)}
+            placeholder="z. B. Entwurfsplanung"
+            required
+            value={name}
+          />
+        </div>
+        <div className="col-6 col-md-3">
+          <label className="form-label" htmlFor="estimate-create-work-stage">
+            LPH
+          </label>
+          <input
+            className="form-control"
+            id="estimate-create-work-stage"
+            maxLength={estimateTextLimits.workStage}
+            onChange={(event) => setWorkStage(event.target.value)}
+            placeholder="z. B. LPH 3"
+            value={workStage}
+          />
+        </div>
+        <div className="col-6 col-md-3">
+          <label className="form-label" htmlFor="estimate-create-date">
+            Datum
+          </label>
+          <input
+            className="form-control"
+            id="estimate-create-date"
+            onChange={(event) => setDateIso(event.target.value)}
+            type="date"
+            value={dateIso}
+          />
+        </div>
+        <div className="col-12 col-md-6">
+          <label className="form-label" htmlFor="estimate-create-template">
+            Inhalt
+          </label>
+          <select
+            className="form-select"
+            id="estimate-create-template"
+            onChange={(event) =>
+              setTemplate(event.target.value as EstimateBalanceTemplate)
+            }
+            value={template}
+          >
+            <option value="kg400">Vorlage KG 400</option>
+            <option value="empty">Leer</option>
+            <option disabled={!balances.length} value="copy">
+              Kopie von …
+            </option>
+          </select>
+        </div>
+        {template === "copy" ? (
+          <div className="col-12 col-md-6">
+            <label className="form-label" htmlFor="estimate-create-copy-from">
+              Kopie von Stand
+            </label>
+            <select
+              className="form-select"
+              id="estimate-create-copy-from"
+              onChange={(event) => setCopyFromBalanceId(event.target.value)}
+              required
+              value={copyFromBalanceId}
+            >
+              {balances.map((balance) => (
+                <option key={balance.id} value={balance.id}>
+                  {balance.workStage ? `${balance.name} (${balance.workStage})` : balance.name}
+                </option>
+              ))}
+            </select>
+          </div>
+        ) : null}
+        <div className="col-12">
+          <p className="text-secondary small mb-0">
+            {template === "kg400"
+              ? "Legt die Kostengruppen 410 bis 480 und „Allgemein“ ohne Einträge an."
+              : template === "empty"
+                ? "Legt einen Stand ohne Kostengruppen an."
+                : "Übernimmt alle Kostengruppen und Zeilen des gewählten Stands."}
+          </p>
+        </div>
+      </div>
+    </FormModal>
+  );
+}

src/frontend/estimate-balance/estimate-balance-document.ts

@@ -0,0 +1,298 @@
+// Pure, immutable editing rules for one "Grobe Leistungsbilanz" document.
+// The editor keeps the complete document as local draft and saves it as a
+// whole (PUT), so every edit is a function draft → new draft.
+import type {
+  EstimateBalanceSnapshot,
+  EstimateGroupSnapshot,
+  EstimateRowSnapshot,
+} from "../../shared/estimate-balance/estimate-balance";
+import { createClientId } from "../utils/client-id";
+
+export type MoveDirection = -1 | 1;
+
+/** Maximum text lengths accepted by the server. */
+export const estimateTextLimits = {
+  balanceName: 200,
+  workStage: 50,
+  costGroup: 20,
+  groupTitle: 200,
+  groupEditor: 100,
+  supply: 50,
+  rowName: 200,
+  remark: 500,
+} as const;
+
+export type EstimateRowPatch = Partial<Omit<EstimateRowSnapshot, "id" | "sortOrder">>;
+export type EstimateGroupPatch = Partial<Pick<EstimateGroupSnapshot, "costGroup" | "title" | "editor">>;
+
+export function createEstimateRow(
+  sortOrder: number,
+  createId: () => string = createClientId
+): EstimateRowSnapshot {
+  return {
+    id: createId(),
+    sortOrder,
+    supply: null,
+    name: "",
+    quantity: 1,
+    unit: "piece",
+    connection: null,
+    powerPerUnitW: 0,
+    simultaneityFactor: 1,
+    cosPhi: 1,
+    safetySupply: false,
+    remark: null,
+  };
+}
+
+export function createEstimateGroup(
+  input: { costGroup: string; title: string; editor?: string | null },
+  sortOrder: number,
+  createId: () => string = createClientId
+): EstimateGroupSnapshot {
+  return {
+    id: createId(),
+    costGroup: input.costGroup,
+    title: input.title,
+    editor: input.editor ?? null,
+    sortOrder,
+    rows: [],
+  };
+}
+
+function bySortOrder<T extends { sortOrder: number }>(left: T, right: T) {
+  return left.sortOrder - right.sortOrder;
+}
+
+/** Orders groups and rows by sortOrder and renumbers both from 0. */
+export function normalizeEstimateSortOrder(
+  balance: EstimateBalanceSnapshot
+): EstimateBalanceSnapshot {
+  return {
+    ...balance,
+    groups: [...balance.groups].sort(bySortOrder).map((group, groupIndex) => ({
+      ...group,
+      sortOrder: groupIndex,
+      rows: [...group.rows].sort(bySortOrder).map((row, rowIndex) => ({
+        ...row,
+        sortOrder: rowIndex,
+      })),
+    })),
+  };
+}
+
+function renumber<T extends { sortOrder: number }>(items: T[]): T[] {
+  return items.map((item, index) =>
+    item.sortOrder === index ? item : { ...item, sortOrder: index }
+  );
+}
+
+function mapGroup(
+  balance: EstimateBalanceSnapshot,
+  groupId: string,
+  update: (group: EstimateGroupSnapshot) => EstimateGroupSnapshot
+): EstimateBalanceSnapshot {
+  let changed = false;
+  const groups = balance.groups.map((group) => {
+    if (group.id !== groupId) {
+      return group;
+    }
+    const next = update(group);
+    changed = next !== group;
+    return next;
+  });
+  // An unknown group or a no-op keeps the identical document.
+  return changed ? { ...balance, groups } : balance;
+}
+
+function moveItem<T>(items: T[], index: number, direction: MoveDirection): T[] | null {
+  const target = index + direction;
+  if (index < 0 || target < 0 || target >= items.length) {
+    return null;
+  }
+  const next = [...items];
+  [next[index], next[target]] = [next[target]!, next[index]!];
+  return next;
+}
+
+/** Appends a row (or inserts it after `afterRowId`) and returns the new row id. */
+export function addEstimateRow(
+  balance: EstimateBalanceSnapshot,
+  groupId: string,
+  options: { afterRowId?: string; createId?: () => string } = {}
+): { balance: EstimateBalanceSnapshot; rowId: string | null } {
+  let rowId: string | null = null;
+  const next = mapGroup(balance, groupId, (group) => {
+    const row = createEstimateRow(0, options.createId);
+    rowId = row.id;
+    const afterIndex = options.afterRowId
+      ? group.rows.findIndex((candidate) => candidate.id === options.afterRowId)
+      : -1;
+    const rows = [...group.rows];
+    rows.splice(afterIndex >= 0 ? afterIndex + 1 : rows.length, 0, row);
+    return { ...group, rows: renumber(rows) };
+  });
+  return { balance: next, rowId };
+}
+
+export function updateEstimateRow(
+  balance: EstimateBalanceSnapshot,
+  groupId: string,
+  rowId: string,
+  patch: EstimateRowPatch
+): EstimateBalanceSnapshot {
+  return mapGroup(balance, groupId, (group) => ({
+    ...group,
+    rows: group.rows.map((row) => (row.id === rowId ? { ...row, ...patch } : row)),
+  }));
+}
+
+export function removeEstimateRow(
+  balance: EstimateBalanceSnapshot,
+  groupId: string,
+  rowId: string
+): EstimateBalanceSnapshot {
+  return mapGroup(balance, groupId, (group) => ({
+    ...group,
+    rows: renumber(group.rows.filter((row) => row.id !== rowId)),
+  }));
+}
+
+export function moveEstimateRow(
+  balance: EstimateBalanceSnapshot,
+  groupId: string,
+  rowId: string,
+  direction: MoveDirection
+): EstimateBalanceSnapshot {
+  return mapGroup(balance, groupId, (group) => {
+    const rows = moveItem(
+      group.rows,
+      group.rows.findIndex((row) => row.id === rowId),
+      direction
+    );
+    return rows ? { ...group, rows: renumber(rows) } : group;
+  });
+}
+
+/** Appends a group and returns its id. */
+export function addEstimateGroup(
+  balance: EstimateBalanceSnapshot,
+  input: { costGroup: string; title: string; editor?: string | null },
+  createId: () => string = createClientId
+): { balance: EstimateBalanceSnapshot; groupId: string } {
+  const group = createEstimateGroup(input, balance.groups.length, createId);
+  return {
+    balance: { ...balance, groups: renumber([...balance.groups, group]) },
+    groupId: group.id,
+  };
+}
+
+export function updateEstimateGroup(
+  balance: EstimateBalanceSnapshot,
+  groupId: string,
+  patch: EstimateGroupPatch
+): EstimateBalanceSnapshot {
+  return mapGroup(balance, groupId, (group) => ({ ...group, ...patch }));
+}
+
+export function removeEstimateGroup(
+  balance: EstimateBalanceSnapshot,
+  groupId: string
+): EstimateBalanceSnapshot {
+  const groups = balance.groups.filter((group) => group.id !== groupId);
+  return groups.length === balance.groups.length
+    ? balance
+    : { ...balance, groups: renumber(groups) };
+}
+
+export function moveEstimateGroup(
+  balance: EstimateBalanceSnapshot,
+  groupId: string,
+  direction: MoveDirection
+): EstimateBalanceSnapshot {
+  const groups = moveItem(
+    balance.groups,
+    balance.groups.findIndex((group) => group.id === groupId),
+    direction
+  );
+  return groups ? { ...balance, groups: renumber(groups) } : balance;
+}
+
+function requiredText(value: string) {
+  return value.trim();
+}
+
+function optionalText(value: string | null) {
+  const trimmed = value?.trim() ?? "";
+  return trimmed ? trimmed : null;
+}
+
+/**
+ * The exact document the server accepts: strings trimmed, empty optional
+ * texts as null, sort orders continuous. Only fields of the shared snapshot
+ * type are copied, so no UI state can leak into the request.
+ */
+export function toSaveableEstimateBalance(
+  balance: EstimateBalanceSnapshot
+): EstimateBalanceSnapshot {
+  const normalized = normalizeEstimateSortOrder(balance);
+  return {
+    id: normalized.id,
+    projectId: normalized.projectId,
+    name: requiredText(normalized.name),
+    workStage: optionalText(normalized.workStage),
+    dateIso: normalized.dateIso || null,
+    reserveAvPercent: normalized.reserveAvPercent,
+    reserveSvPercent: normalized.reserveSvPercent,
+    sortOrder: normalized.sortOrder,
+    groups: normalized.groups.map((group) => ({
+      id: group.id,
+      costGroup: requiredText(group.costGroup),
+      title: requiredText(group.title),
+      editor: optionalText(group.editor),
+      sortOrder: group.sortOrder,
+      rows: group.rows.map((row) => ({
+        id: row.id,
+        sortOrder: row.sortOrder,
+        supply: optionalText(row.supply),
+        name: requiredText(row.name),
+        quantity: row.quantity,
+        unit: row.unit,
+        connection: row.connection,
+        powerPerUnitW: row.powerPerUnitW,
+        simultaneityFactor: row.simultaneityFactor,
+        cosPhi: row.cosPhi,
+        safetySupply: row.safetySupply,
+        remark: optionalText(row.remark),
+      })),
+    })),
+  };
+}
+
+/** Stable comparison key of the saveable document (dirty detection). */
+export function estimateBalanceFingerprint(balance: EstimateBalanceSnapshot): string {
+  return JSON.stringify(toSaveableEstimateBalance(balance));
+}
+
+/**
+ * German problems that would make the server reject the document. The
+ * editor never saves while this list is not empty.
+ */
+export function validateEstimateBalance(balance: EstimateBalanceSnapshot): string[] {
+  const problems: string[] = [];
+  const saveable = toSaveableEstimateBalance(balance);
+  if (!saveable.name) {
+    problems.push("Die Bezeichnung des Stands darf nicht leer sein.");
+  }
+  for (const group of saveable.groups) {
+    if (!group.title) {
+      problems.push(`Kostengruppe ${group.costGroup || "ohne Nummer"}: Titel fehlt.`);
+    }
+  }
+  return problems;
+}
+
+export function createCopyName(name: string) {
+  const copyName = `${name.trim()} (Kopie)`;
+  return copyName.slice(0, estimateTextLimits.balanceName);
+}

src/frontend/estimate-balance/estimate-balance-format.ts

@@ -0,0 +1,122 @@
+// Pure parsing and formatting rules of the "Grobe Leistungsbilanz" editor.
+// Numbers are entered and shown in German notation. As in the circuit list
+// editor, only "," is accepted as decimal separator: a "." is ambiguous
+// (decimal point or thousands separator) and is rejected instead of guessed.
+import { roundEstimateValue } from "../../shared/estimate-balance/estimate-balance";
+
+export type DecimalParseResult =
+  | { ok: true; value: number }
+  | { ok: false; error: string };
+
+export interface DecimalRange {
+  min?: number;
+  /** Excludes `min` itself (e.g. cos φ > 0). */
+  minExclusive?: boolean;
+  max?: number;
+}
+
+const DECIMAL_PATTERN = /^[+-]?(\d+(,\d*)?|,\d+)$/;
+
+function formatBound(value: number) {
+  return value.toLocaleString("de-DE", { maximumFractionDigits: 6, useGrouping: false });
+}
+
+export function parseGermanDecimal(text: string, range: DecimalRange = {}): DecimalParseResult {
+  const trimmed = text.trim();
+  if (!trimmed) {
+    return { ok: false, error: "Bitte einen Wert eingeben." };
+  }
+  if (trimmed.includes(".")) {
+    return { ok: false, error: "Dezimalstellen mit Komma eingeben (z. B. 0,8)." };
+  }
+  if (!DECIMAL_PATTERN.test(trimmed)) {
+    return { ok: false, error: "Ungültiger Zahlenwert." };
+  }
+  const value = Number(trimmed.replace(",", "."));
+  if (!Number.isFinite(value)) {
+    return { ok: false, error: "Ungültiger Zahlenwert." };
+  }
+  if (range.min !== undefined) {
+    if (range.minExclusive ? value <= range.min : value < range.min) {
+      return {
+        ok: false,
+        error: range.minExclusive
+          ? `Der Wert muss größer als ${formatBound(range.min)} sein.`
+          : `Der Wert darf nicht kleiner als ${formatBound(range.min)} sein.`,
+      };
+    }
+  }
+  if (range.max !== undefined && value > range.max) {
+    return { ok: false, error: `Der Wert darf nicht größer als ${formatBound(range.max)} sein.` };
+  }
+  return { ok: true, value };
+}
+
+/** Value ranges accepted by the server for the numeric document fields. */
+export const estimateNumberRanges = {
+  quantity: { min: 0 },
+  powerPerUnitW: { min: 0 },
+  simultaneityFactor: { min: 0, max: 1 },
+  cosPhi: { min: 0, minExclusive: true, max: 1 },
+  reservePercent: { min: 0, max: 100 },
+} satisfies Record<string, DecimalRange>;
+
+/**
+ * Text of a numeric input field: German comma, no thousands separator, so the
+ * shown text can be parsed again unchanged.
+ */
+export function formatDecimalInput(value: number, maximumFractionDigits = 6): string {
+  return value.toLocaleString("de-DE", { maximumFractionDigits, useGrouping: false });
+}
+
+/**
+ * Read-only display of a calculated value with thousands separator ("1.200",
+ * "30,24"). The value is rounded half away from zero first, like Excel does
+ * (40,175 → 40,18 instead of the binary-rounded 40,17).
+ */
+export function formatGermanNumber(
+  value: number,
+  minimumFractionDigits: number,
+  maximumFractionDigits = minimumFractionDigits
+): string {
+  const rounded = roundEstimateValue(value, maximumFractionDigits);
+  // "+ 0" turns -0 into 0 and avoids "-0,00".
+  return (rounded + 0).toLocaleString("de-DE", {
+    minimumFractionDigits,
+    maximumFractionDigits,
+  });
+}
+
+export function formatKw(value: number) {
+  return formatGermanNumber(value, 2);
+}
+
+export function formatAmpere(value: number) {
+  return formatGermanNumber(value, 2);
+}
+
+export function formatSignedKw(value: number) {
+  const text = formatKw(value);
+  return value > 0 && text !== "0,00" ? `+${text}` : text;
+}
+
+export function formatDeltaPercent(value: number | null) {
+  if (value === null) {
+    return "–";
+  }
+  const text = formatGermanNumber(value, 1);
+  return `${value > 0 && text !== "0,0" ? "+" : ""}${text} %`;
+}
+
+/** "2026-09-26" → "26.09.2026"; empty/invalid → "–". */
+export function formatIsoDateGerman(dateIso: string | null): string {
+  const match = dateIso?.match(/^(\d{4})-(\d{2})-(\d{2})$/);
+  return match ? `${match[3]}.${match[2]}.${match[1]}` : "–";
+}
+
+/** Local calendar date as YYYY-MM-DD (not UTC, so late evenings stay today). */
+export function getTodayIsoDate(now: Date = new Date()): string {
+  const month = String(now.getMonth() + 1).padStart(2, "0");
+  const day = String(now.getDate()).padStart(2, "0");
+  return `${now.getFullYear()}-${month}-${day}`;
+}

src/frontend/estimate-balance/estimate-balance-sheet.tsx

@@ -0,0 +1,669 @@
+"use client";
+
+import type { ReactNode } from "react";
+import { ArrowDown, ArrowUp, Pencil, Plus, Trash2 } from "lucide-react";
+import {
+  calculateEstimateBalance,
+  calculateEstimateRow,
+  estimateRowConnectionLabels,
+  estimateRowUnitLabels,
+  type EstimateBalanceSnapshot,
+  type EstimateGroupSnapshot,
+  type EstimatePower,
+  type EstimateRowConnection,
+  type EstimateRowSnapshot,
+  type EstimateRowUnit,
+} from "../../shared/estimate-balance/estimate-balance";
+import {
+  addEstimateRow,
+  estimateTextLimits,
+  moveEstimateGroup,
+  removeEstimateGroup,
+  removeEstimateRow,
+  updateEstimateGroup,
+  updateEstimateRow,
+  type EstimateRowPatch,
+} from "./estimate-balance-document";
+import {
+  estimateNumberRanges,
+  formatAmpere,
+  formatDecimalInput,
+  formatKw,
+  parseGermanDecimal,
+  type DecimalRange,
+  formatGermanNumber,
+} from "./estimate-balance-format";
+import { DraftInput } from "./estimate-draft-input";
+
+export type EstimateBalanceUpdate = (
+  update: (balance: EstimateBalanceSnapshot) => EstimateBalanceSnapshot
+) => void;
+
+interface EstimateBalanceSheetProps {
+  balance: EstimateBalanceSnapshot;
+  disabled: boolean;
+  onAddGroup: () => void;
+  onChange: EstimateBalanceUpdate;
+  onEditGroup: (group: EstimateGroupSnapshot) => void;
+  onOpenGzfPicker: (groupId: string, rowId: string) => void;
+  onValidityChange: (fieldKey: string, isValid: boolean) => void;
+  threePhaseVoltageV: number;
+}
+
+// Leading columns up to cos φ; the power columns follow.
+const LEADING_COLUMN_COUNT = 9;
+const COLUMN_COUNT = 16;
+
+/** Suggested supply values; free text stays possible. */
+const SUPPLY_SUGGESTIONS = ["ELT", "MSR"];
+const SUPPLY_LIST_ID = "estimate-supply-options";
+
+function NumberInput({
+  ariaLabel,
+  disabled,
+  fieldKey,
+  onCommit,
+  onValidityChange,
+  range,
+  value,
+}: {
+  ariaLabel: string;
+  disabled: boolean;
+  fieldKey: string;
+  onCommit: (value: number) => void;
+  onValidityChange: (fieldKey: string, isValid: boolean) => void;
+  range: DecimalRange;
+  value: number;
+}) {
+  return (
+    <DraftInput
+      ariaLabel={ariaLabel}
+      className="estimate-cell-input is-numeric"
+      disabled={disabled}
+      format={(current: number) => formatDecimalInput(current)}
+      inputMode="decimal"
+      printFormat={(current: number) => formatGermanNumber(current, 0, 3)}
+      onCommit={onCommit}
+      onValidityChange={(isValid) => onValidityChange(fieldKey, isValid)}
+      parse={(text) => parseGermanDecimal(text, range)}
+      value={value}
+    />
+  );
+}
+
+function supplyOptions(balance: EstimateBalanceSnapshot): string[] {
+  const used = balance.groups.flatMap((group) =>
+    group.rows.map((row) => row.supply?.trim() ?? "")
+  );
+  return [...new Set([...SUPPLY_SUGGESTIONS, ...used.filter(Boolean)])];
+}
+
+function TextInput({
+  ariaLabel,
+  disabled,
+  list,
+  maxLength,
+  onChange,
+  placeholder,
+  value,
+}: {
+  ariaLabel: string;
+  disabled: boolean;
+  list?: string;
+  maxLength: number;
+  onChange: (value: string) => void;
+  placeholder?: string;
+  value: string | null;
+}) {
+  return (
+    <>
+      <input
+        aria-label={ariaLabel}
+        className="estimate-cell-input"
+        disabled={disabled}
+        list={list}
+        maxLength={maxLength}
+        onChange={(event) => onChange(event.target.value)}
+        placeholder={placeholder}
+        type="text"
+        value={value ?? ""}
+      />
+      <span className="estimate-print-value">{value ?? ""}</span>
+    </>
+  );
+}
+
+function IconButton({
+  children,
+  disabled,
+  label,
+  onClick,
+  variant = "secondary",
+}: {
+  children: ReactNode;
+  disabled: boolean;
+  label: string;
+  onClick: () => void;
+  variant?: "secondary" | "danger" | "primary";
+}) {
+  return (
+    <button
+      aria-label={label}
+      className={`btn btn-sm btn-outline-${variant} estimate-icon-button`}
+      disabled={disabled}
+      onClick={onClick}
+      title={label}
+      type="button"
+    >
+      {children}
+    </button>
+  );
+}
+
+function PowerCells({ power, className = "" }: { power: EstimatePower; className?: string }) {
+  return (
+    <>
+      <td className={`estimate-number ${className}`}>{formatKw(power.kw)}</td>
+      <td className={`estimate-number ${className}`}>{formatKw(power.kva)}</td>
+    </>
+  );
+}
+
+function groupLabel(group: EstimateGroupSnapshot) {
+  return [group.costGroup, group.title].filter(Boolean).join(" ");
+}
+
+function EstimateRowLine({
+  disabled,
+  group,
+  onChange,
+  onOpenGzfPicker,
+  onValidityChange,
+  row,
+  rowIndex,
+}: {
+  disabled: boolean;
+  group: EstimateGroupSnapshot;
+  onChange: EstimateBalanceUpdate;
+  onOpenGzfPicker: (groupId: string, rowId: string) => void;
+  onValidityChange: (fieldKey: string, isValid: boolean) => void;
+  row: EstimateRowSnapshot;
+  rowIndex: number;
+}) {
+  const result = calculateEstimateRow(row);
+  const rowLabel = `${groupLabel(group)}, Zeile ${rowIndex + 1}`;
+  const fieldKey = (field: string) => `${row.id}:${field}`;
+
+  function patch(rowPatch: EstimateRowPatch) {
+    onChange((balance) => updateEstimateRow(balance, group.id, row.id, rowPatch));
+  }
+
+  return (
+    <tr className="estimate-row">
+      <td className="estimate-cost-group-cell" />
+      <td>
+        <TextInput
+          ariaLabel={`Versorgung (${rowLabel})`}
+          disabled={disabled}
+          list={SUPPLY_LIST_ID}
+          maxLength={estimateTextLimits.supply}
+          onChange={(supply) => patch({ supply })}
+          placeholder="ELT"
+          value={row.supply}
+        />
+      </td>
+      <td className="estimate-name-cell">
+        <TextInput
+          ariaLabel={`Verbraucher / Fläche (${rowLabel})`}
+          disabled={disabled}
+          maxLength={estimateTextLimits.rowName}
+          onChange={(name) => patch({ name })}
+          placeholder="Verbraucher oder Fläche"
+          value={row.name}
+        />
+      </td>
+      <td>
+        <NumberInput
+          ariaLabel={`Anzahl / Fläche (${rowLabel})`}
+          disabled={disabled}
+          fieldKey={fieldKey("quantity")}
+          onCommit={(quantity) => patch({ quantity })}
+          onValidityChange={onValidityChange}
+          range={estimateNumberRanges.quantity}
+          value={row.quantity}
+        />
+      </td>
+      <td>
+        <select
+          aria-label={`Einheit (${rowLabel})`}
+          className="estimate-cell-select"
+          disabled={disabled}
+          onChange={(event) => patch({ unit: event.target.value as EstimateRowUnit })}
+          value={row.unit}
+        >
+          {(Object.keys(estimateRowUnitLabels) as EstimateRowUnit[]).map((unit) => (
+            <option key={unit} value={unit}>
+              {estimateRowUnitLabels[unit]}
+            </option>
+          ))}
+        </select>
+        <span className="estimate-print-value">{estimateRowUnitLabels[row.unit]}</span>
+      </td>
+      <td>
+        <select
+          aria-label={`Anschluss (${rowLabel})`}
+          className="estimate-cell-select"
+          disabled={disabled}
+          onChange={(event) =>
+            patch({
+              connection: (event.target.value || null) as EstimateRowConnection | null,
+            })
+          }
+          value={row.connection ?? ""}
+        >
+          <option value="">–</option>
+          {(Object.keys(estimateRowConnectionLabels) as EstimateRowConnection[]).map(
+            (connection) => (
+              <option key={connection} value={connection}>
+                {estimateRowConnectionLabels[connection]}
+              </option>
+            )
+          )}
+        </select>
+        <span className="estimate-print-value">
+          {row.connection ? estimateRowConnectionLabels[row.connection] : ""}
+        </span>
+      </td>
+      <td>
+        <div className="estimate-unit-input">
+          <NumberInput
+            ariaLabel={`Einzelleistung in ${row.unit === "area" ? "W/m²" : "W"} (${rowLabel})`}
+            disabled={disabled}
+            fieldKey={fieldKey("powerPerUnitW")}
+            onCommit={(powerPerUnitW) => patch({ powerPerUnitW })}
+            onValidityChange={onValidityChange}
+            range={estimateNumberRanges.powerPerUnitW}
+            value={row.powerPerUnitW}
+          />
+          <span className="estimate-unit-label">{row.unit === "area" ? "W/m²" : "W"}</span>
+        </div>
+      </td>
+      <td>
+        <div className="estimate-gzf-input">
+          <NumberInput
+            ariaLabel={`Gleichzeitigkeitsfaktor (${rowLabel})`}
+            disabled={disabled}
+            fieldKey={fieldKey("simultaneityFactor")}
+            onCommit={(simultaneityFactor) => patch({ simultaneityFactor })}
+            onValidityChange={onValidityChange}
+            range={estimateNumberRanges.simultaneityFactor}
+            value={row.simultaneityFactor}
+          />
+          <button
+            aria-label={`Gleichzeitigkeitsfaktor nach AMEV wählen (${rowLabel})`}
+            className="estimate-amev-button estimate-no-print"
+            disabled={disabled}
+            onClick={() => onOpenGzfPicker(group.id, row.id)}
+            title="Gleichzeitigkeitsfaktor nach AMEV wählen"
+            type="button"
+          >
+            AMEV
+          </button>
+        </div>
+      </td>
+      <td>
+        <NumberInput
+          ariaLabel={`cos φ (${rowLabel})`}
+          disabled={disabled}
+          fieldKey={fieldKey("cosPhi")}
+          onCommit={(cosPhi) => patch({ cosPhi })}
+          onValidityChange={onValidityChange}
+          range={estimateNumberRanges.cosPhi}
+          value={row.cosPhi}
+        />
+      </td>
+      <PowerCells power={result.av} />
+      <td className="estimate-center">
+        <input
+          aria-label={`Sicherheitsversorgung (${rowLabel})`}
+          checked={row.safetySupply}
+          className="form-check-input estimate-no-print"
+          disabled={disabled}
+          onChange={(event) => patch({ safetySupply: event.target.checked })}
+          type="checkbox"
+        />
+        <span className="estimate-print-value">{row.safetySupply ? "ja" : "nein"}</span>
+      </td>
+      <PowerCells
+        className={row.safetySupply ? "" : "is-muted"}
+        power={result.sv}
+      />
+      <td>
+        <TextInput
+          ariaLabel={`Anmerkung (${rowLabel})`}
+          disabled={disabled}
+          maxLength={estimateTextLimits.remark}
+          onChange={(remark) => patch({ remark })}
+          value={row.remark}
+        />
+      </td>
+      <td className="estimate-actions-cell estimate-no-print">
+        <IconButton
+          disabled={disabled}
+          label={`Zeile löschen (${rowLabel})`}
+          onClick={() => onChange((balance) => removeEstimateRow(balance, group.id, row.id))}
+          variant="danger"
+        >
+          <Trash2 aria-hidden="true" size={13} />
+        </IconButton>
+      </td>
+    </tr>
+  );
+}
+
+/**
+ * Spreadsheet-like editor in the layout of the office template
+ * "Leistungsbilanz – KG400": one section per cost group with title and
+ * subtotal row, totals, reserve and maximum current at the end.
+ */
+export function EstimateBalanceSheet({
+  balance,
+  disabled,
+  onAddGroup,
+  onChange,
+  onEditGroup,
+  onOpenGzfPicker,
+  onValidityChange,
+  threePhaseVoltageV,
+}: EstimateBalanceSheetProps) {
+  const result = calculateEstimateBalance(balance, threePhaseVoltageV);
+
+  function confirmRemoveGroup(group: EstimateGroupSnapshot) {
+    const rowText =
+      group.rows.length === 1 ? "1 Zeile" : `${group.rows.length} Zeilen`;
+    if (
+      window.confirm(
+        `Kostengruppe „${groupLabel(group)}“ mit ${rowText} wirklich löschen?`
+      )
+    ) {
+      onChange((current) => removeEstimateGroup(current, group.id));
+    }
+  }
+
+  return (
+    <div className="estimate-sheet-wrap">
+      <datalist id={SUPPLY_LIST_ID}>
+        {supplyOptions(balance).map((supply) => (
+          <option key={supply} value={supply} />
+        ))}
+      </datalist>
+      <table className="estimate-sheet">
+        <colgroup>
+          <col className="estimate-col-kg" />
+          <col className="estimate-col-supply" />
+          <col className="estimate-col-name" />
+          <col className="estimate-col-quantity" />
+          <col className="estimate-col-unit" />
+          <col className="estimate-col-connection" />
+          <col className="estimate-col-power" />
+          <col className="estimate-col-gzf" />
+          <col className="estimate-col-cosphi" />
+          <col className="estimate-col-result" />
+          <col className="estimate-col-result" />
+          <col className="estimate-col-sv" />
+          <col className="estimate-col-result" />
+          <col className="estimate-col-result" />
+          <col className="estimate-col-remark" />
+          <col className="estimate-col-actions" />
+        </colgroup>
+        <thead>
+          <tr>
+            <th rowSpan={2}>KG</th>
+            <th rowSpan={2}>
+              Versorgung
+              <span className="estimate-th-hint">ELT/MSR …</span>
+            </th>
+            <th rowSpan={2}>Verbraucher / Flächen</th>
+            <th colSpan={2}>
+              Anzahl / Fläche
+              <span className="estimate-th-hint">St. / m²</span>
+            </th>
+            <th rowSpan={2}>
+              Anschl.
+              <span className="estimate-th-hint">Fest/Steckd.</span>
+            </th>
+            <th rowSpan={2}>
+              Einzelleist.
+              <span className="estimate-th-hint">W bzw. W/m²</span>
+            </th>
+            <th rowSpan={2}>GL-Faktor</th>
+            <th rowSpan={2}>cos φ</th>
+            <th colSpan={2}>Nötige AV-Leistung</th>
+            <th colSpan={3}>Sicherheitsversorgung (SV)</th>
+            <th rowSpan={2}>Anmerkungen</th>
+            <th aria-label="Aktionen" className="estimate-no-print" rowSpan={2} />
+          </tr>
+          <tr>
+            <th>Wert</th>
+            <th>Einh.</th>
+            <th>kW</th>
+            <th>kVA</th>
+            <th>ja/nein</th>
+            <th>kW</th>
+            <th>kVA</th>
+          </tr>
+        </thead>
+        {balance.groups.map((group, groupIndex) => {
+          const groupResult = result.groups[groupIndex]!;
+          const label = groupLabel(group) || "Kostengruppe";
+          return (
+            <tbody className="estimate-group" key={group.id}>
+              <tr className="estimate-group-title-row">
+                <td className="estimate-cost-group-cell">{group.costGroup}</td>
+                <td colSpan={COLUMN_COUNT - 2}>
+                  <div className="estimate-group-title">
+                    <span className="estimate-group-name">{group.title}</span>
+                    <label
+                      className={
+                        group.editor?.trim()
+                          ? "estimate-group-editor"
+                          : "estimate-group-editor is-empty"
+                      }
+                    >
+                      <span>bearbeitet von</span>
+                      <input
+                        aria-label={`Bearbeitet von (${label})`}
+                        className="estimate-cell-input"
+                        disabled={disabled}
+                        maxLength={estimateTextLimits.groupEditor}
+                        onChange={(event) =>
+                          onChange((current) =>
+                            updateEstimateGroup(current, group.id, {
+                              editor: event.target.value,
+                            })
+                          )
+                        }
+                        placeholder="Gewerk / Name"
+                        type="text"
+                        value={group.editor ?? ""}
+                      />
+                      <span className="estimate-print-value">{group.editor ?? ""}</span>
+                    </label>
+                  </div>
+                </td>
+                <td className="estimate-actions-cell estimate-no-print">
+                  <div className="estimate-group-actions">
+                    <IconButton
+                      disabled={disabled}
+                      label={`Zeile hinzufügen (${label})`}
+                      onClick={() =>
+                        onChange((current) => addEstimateRow(current, group.id).balance)
+                      }
+                      variant="primary"
+                    >
+                      <Plus aria-hidden="true" size={13} />
+                    </IconButton>
+                    <IconButton
+                      disabled={disabled}
+                      label={`Gruppe bearbeiten (${label})`}
+                      onClick={() => onEditGroup(group)}
+                    >
+                      <Pencil aria-hidden="true" size={13} />
+                    </IconButton>
+                    <IconButton
+                      disabled={disabled || groupIndex === 0}
+                      label={`Gruppe nach oben (${label})`}
+                      onClick={() =>
+                        onChange((current) => moveEstimateGroup(current, group.id, -1))
+                      }
+                    >
+                      <ArrowUp aria-hidden="true" size={13} />
+                    </IconButton>
+                    <IconButton
+                      disabled={disabled || groupIndex === balance.groups.length - 1}
+                      label={`Gruppe nach unten (${label})`}
+                      onClick={() =>
+                        onChange((current) => moveEstimateGroup(current, group.id, 1))
+                      }
+                    >
+                      <ArrowDown aria-hidden="true" size={13} />
+                    </IconButton>
+                    <IconButton
+                      disabled={disabled}
+                      label={`Gruppe löschen (${label})`}
+                      onClick={() => confirmRemoveGroup(group)}
+                      variant="danger"
+                    >
+                      <Trash2 aria-hidden="true" size={13} />
+                    </IconButton>
+                  </div>
+                </td>
+              </tr>
+              {group.rows.map((row, rowIndex) => (
+                <EstimateRowLine
+                  disabled={disabled}
+                  group={group}
+                  key={row.id}
+                  onChange={onChange}
+                  onOpenGzfPicker={onOpenGzfPicker}
+                  onValidityChange={onValidityChange}
+                  row={row}
+                  rowIndex={rowIndex}
+                />
+              ))}
+              {!group.rows.length ? (
+                <tr className="estimate-empty-row estimate-no-print">
+                  <td />
+                  <td colSpan={COLUMN_COUNT - 1}>
+                    Noch keine Einträge – mit „+“ eine Zeile hinzufügen.
+                  </td>
+                </tr>
+              ) : null}
+              <tr className="estimate-subtotal-row">
+                <td colSpan={LEADING_COLUMN_COUNT} className="estimate-total-label">
+                  Summe {label}
+                </td>
+                <PowerCells power={groupResult.av} />
+                <td />
+                <PowerCells power={groupResult.sv} />
+                <td />
+                <td className="estimate-no-print" />
+              </tr>
+            </tbody>
+          );
+        })}
+        <tfoot>
+          <tr className="estimate-no-print estimate-add-group-row">
+            <td colSpan={COLUMN_COUNT}>
+              <button
+                className="btn btn-sm btn-outline-primary"
+                disabled={disabled}
+                onClick={onAddGroup}
+                type="button"
+              >
+                <Plus aria-hidden="true" className="me-1" size={14} />
+                Kostengruppe hinzufügen
+              </button>
+            </td>
+          </tr>
+          <tr className="estimate-total-row">
+            <td colSpan={LEADING_COLUMN_COUNT} className="estimate-total-label">
+              Gesamtsumme
+            </td>
+            <PowerCells power={result.total.av} />
+            <td />
+            <PowerCells power={result.total.sv} />
+            <td colSpan={2} />
+          </tr>
+          <tr className="estimate-total-row">
+            <td colSpan={LEADING_COLUMN_COUNT - 1} className="estimate-total-label">
+              Reserveleistung
+            </td>
+            <td>
+              <div className="estimate-unit-input">
+                <NumberInput
+                  ariaLabel="Reserve AV in Prozent"
+                  disabled={disabled}
+                  fieldKey="balance:reserveAvPercent"
+                  onCommit={(reserveAvPercent) =>
+                    onChange((current) => ({ ...current, reserveAvPercent }))
+                  }
+                  onValidityChange={onValidityChange}
+                  range={estimateNumberRanges.reservePercent}
+                  value={balance.reserveAvPercent}
+                />
+                <span className="estimate-unit-label">%</span>
+              </div>
+            </td>
+            <PowerCells power={result.reserve.av} />
+            <td>
+              <div className="estimate-unit-input">
+                <NumberInput
+                  ariaLabel="Reserve SV in Prozent"
+                  disabled={disabled}
+                  fieldKey="balance:reserveSvPercent"
+                  onCommit={(reserveSvPercent) =>
+                    onChange((current) => ({ ...current, reserveSvPercent }))
+                  }
+                  onValidityChange={onValidityChange}
+                  range={estimateNumberRanges.reservePercent}
+                  value={balance.reserveSvPercent}
+                />
+                <span className="estimate-unit-label">%</span>
+              </div>
+            </td>
+            <PowerCells power={result.reserve.sv} />
+            <td colSpan={2} />
+          </tr>
+          <tr className="estimate-total-row is-strong">
+            <td colSpan={LEADING_COLUMN_COUNT} className="estimate-total-label">
+              Leistung inkl. Reserve
+            </td>
+            <PowerCells power={result.withReserve.av} />
+            <td />
+            <PowerCells power={result.withReserve.sv} />
+            <td colSpan={2} />
+          </tr>
+          <tr className="estimate-total-row">
+            <td colSpan={LEADING_COLUMN_COUNT} className="estimate-total-label">
+              Maximalstrom
+              <span className="estimate-total-hint">
+                {threePhaseVoltageV > 0
+                  ? ` (3~, U = ${formatDecimalInput(threePhaseVoltageV)} V)`
+                  : " (Drehstromspannung im Projekt fehlt)"}
+              </span>
+            </td>
+            <td className="estimate-number" colSpan={2}>
+              {formatAmpere(result.maxCurrentA.av)} A
+            </td>
+            <td />
+            <td className="estimate-number" colSpan={2}>
+              {formatAmpere(result.maxCurrentA.sv)} A
+            </td>
+            <td colSpan={2} />
+          </tr>
+        </tfoot>
+      </table>
+    </div>
+  );
+}

src/frontend/estimate-balance/estimate-comparison-table.tsx

@@ -0,0 +1,88 @@
+"use client";
+
+import {
+  roundEstimateValue,
+  type EstimateComparison,
+} from "../../shared/estimate-balance/estimate-balance";
+import { formatDeltaPercent, formatKw, formatSignedKw } from "./estimate-balance-format";
+
+function deltaClass(deltaKw: number) {
+  if (roundEstimateValue(deltaKw, 2) === 0) {
+    return "estimate-number";
+  }
+  return deltaKw > 0 ? "estimate-number is-over" : "estimate-number is-under";
+}
+
+/** Estimated AV power per cost group vs. the detailed circuit-list rows. */
+export function EstimateComparisonTable({ comparison }: { comparison: EstimateComparison }) {
+  return (
+    <div className="estimate-sheet-wrap">
+      <table className="estimate-sheet estimate-comparison">
+        <thead>
+          <tr>
+            <th>KG</th>
+            <th>Titel</th>
+            <th>geschätzt AV kW</th>
+            <th>detailliert kW</th>
+            <th>Δ kW</th>
+            <th>Δ %</th>
+          </tr>
+        </thead>
+        <tbody>
+          {comparison.groups.map((group) => (
+            <tr key={group.groupId}>
+              <td className="estimate-cost-group-cell">{group.costGroup}</td>
+              <td>
+                {group.title}
+                {group.detailedRowCount ? (
+                  <span className="estimate-th-hint">
+                    {group.detailedRowCount === 1
+                      ? "1 Gerätezeile"
+                      : `${group.detailedRowCount} Gerätezeilen`}
+                  </span>
+                ) : null}
+              </td>
+              <td className="estimate-number">{formatKw(group.estimatedAv.kw)}</td>
+              <td className="estimate-number">{formatKw(group.detailed.kw)}</td>
+              <td className={deltaClass(group.deltaKw)}>{formatSignedKw(group.deltaKw)}</td>
+              <td className={deltaClass(group.deltaKw)}>
+                {formatDeltaPercent(group.deltaPercent)}
+              </td>
+            </tr>
+          ))}
+          <tr className="estimate-unassigned-row">
+            <td />
+            <td>
+              ohne Kostengruppe / nicht zugeordnet
+              {comparison.unassigned.rowCount ? (
+                <span className="estimate-th-hint">
+                  {comparison.unassigned.rowCount === 1
+                    ? "1 Gerätezeile"
+                    : `${comparison.unassigned.rowCount} Gerätezeilen`}
+                </span>
+              ) : null}
+            </td>
+            <td className="estimate-number">–</td>
+            <td className="estimate-number">{formatKw(comparison.unassigned.kw)}</td>
+            <td className="estimate-number">–</td>
+            <td className="estimate-number">–</td>
+          </tr>
+        </tbody>
+        <tfoot>
+          <tr className="estimate-total-row is-strong">
+            <td />
+            <td className="estimate-total-label">Summe</td>
+            <td className="estimate-number">{formatKw(comparison.total.estimatedAv.kw)}</td>
+            <td className="estimate-number">{formatKw(comparison.total.detailed.kw)}</td>
+            <td className={deltaClass(comparison.total.deltaKw)}>
+              {formatSignedKw(comparison.total.deltaKw)}
+            </td>
+            <td className={deltaClass(comparison.total.deltaKw)}>
+              {formatDeltaPercent(comparison.total.deltaPercent)}
+            </td>
+          </tr>
+        </tfoot>
+      </table>
+    </div>
+  );
+}

src/frontend/estimate-balance/estimate-draft-input.tsx

@@ -0,0 +1,112 @@
+"use client";
+
+import { useEffect, useRef, useState } from "react";
+
+export type DraftParseResult<T> = { ok: true; value: T } | { ok: false; error: string };
+
+interface DraftInputProps<T> {
+  ariaLabel: string;
+  className?: string;
+  disabled?: boolean;
+  format: (value: T) => string;
+  /** Printed text; defaults to the input text. */
+  printFormat?: (value: T) => string;
+  inputMode?: "decimal" | "text";
+  maxLength?: number;
+  onCommit: (value: T) => void;
+  /** Reports whether the raw text is currently valid (false while invalid). */
+  onValidityChange?: (isValid: boolean) => void;
+  parse: (text: string) => DraftParseResult<T>;
+  placeholder?: string;
+  value: T;
+}
+
+/**
+ * Input that keeps the raw text the user typed. Only a valid text is
+ * committed into the document; an invalid text stays visible with a red
+ * border and is never saved. A value changed from outside (reload, undo)
+ * replaces the text unless the text already represents that value.
+ */
+export function DraftInput<T>({
+  ariaLabel,
+  className = "estimate-cell-input",
+  disabled,
+  format,
+  printFormat,
+  inputMode = "text",
+  maxLength,
+  onCommit,
+  onValidityChange,
+  parse,
+  placeholder,
+  value,
+}: DraftInputProps<T>) {
+  const [text, setText] = useState(() => format(value));
+  const [error, setError] = useState<string | null>(null);
+  const [syncedValue, setSyncedValue] = useState(value);
+
+  if (!Object.is(syncedValue, value)) {
+    // Adjusting state while rendering (instead of an effect) avoids a frame
+    // with stale text after an external change.
+    setSyncedValue(value);
+    const parsed = parse(text);
+    if (!parsed.ok || !Object.is(parsed.value, value)) {
+      setText(format(value));
+      setError(null);
+    }
+  }
+
+  const validityRef = useRef(onValidityChange);
+  useEffect(() => {
+    validityRef.current = onValidityChange;
+  });
+  const isValid = error === null;
+  useEffect(() => {
+    validityRef.current?.(isValid);
+  }, [isValid]);
+  // A removed input (deleted row) must not leave an invalid marker behind.
+  useEffect(() => () => validityRef.current?.(true), []);
+
+  function handleChange(nextText: string) {
+    setText(nextText);
+    const parsed = parse(nextText);
+    if (!parsed.ok) {
+      setError(parsed.error);
+      return;
+    }
+    setError(null);
+    if (!Object.is(parsed.value, value)) {
+      setSyncedValue(parsed.value);
+      onCommit(parsed.value);
+    }
+  }
+
+  function handleBlur() {
+    // Show the canonical notation again ("0,80" → "0,8") once editing ends.
+    if (error === null) {
+      setText(format(value));
+    }
+  }
+
+  return (
+    <>
+      <input
+        aria-invalid={error ? true : undefined}
+        aria-label={ariaLabel}
+        className={error ? `${className} is-invalid` : className}
+        disabled={disabled}
+        inputMode={inputMode}
+        maxLength={maxLength}
+        onBlur={handleBlur}
+        onChange={(event) => handleChange(event.target.value)}
+        placeholder={placeholder}
+        title={error ?? undefined}
+        type="text"
+        value={text}
+      />
+      <span className="estimate-print-value">
+        {printFormat ? printFormat(value) : error ? format(value) : text}
+      </span>
+    </>
+  );
+}

src/frontend/estimate-balance/estimate-group-modal.tsx

@@ -0,0 +1,128 @@
+"use client";
+
+import { type FormEvent, useState } from "react";
+import { FormModal } from "../components/form-modal";
+import {
+  estimateDefaultGroups,
+  type EstimateGroupSnapshot,
+} from "../../shared/estimate-balance/estimate-balance";
+import { estimateTextLimits } from "./estimate-balance-document";
+
+export interface EstimateGroupFormValues {
+  costGroup: string;
+  title: string;
+  editor: string | null;
+}
+
+interface EstimateGroupModalProps {
+  group: EstimateGroupSnapshot | null;
+  onClose: () => void;
+  onSave: (values: EstimateGroupFormValues) => void;
+}
+
+/** Creates or edits the KG number, title and "bearbeitet von" of one group. */
+export function EstimateGroupModal({ group, onClose, onSave }: EstimateGroupModalProps) {
+  const [costGroup, setCostGroup] = useState(group?.costGroup ?? "");
+  const [title, setTitle] = useState(group?.title ?? "");
+  const [editor, setEditor] = useState(group?.editor ?? "");
+
+  function applyTemplate(index: string) {
+    const template = estimateDefaultGroups[Number(index)];
+    if (template) {
+      setCostGroup(template.costGroup);
+      setTitle(template.title);
+    }
+  }
+
+  function handleSubmit(event: FormEvent<HTMLFormElement>) {
+    event.preventDefault();
+    if (!title.trim()) {
+      return;
+    }
+    onSave({
+      costGroup: costGroup.trim(),
+      title: title.trim(),
+      editor: editor.trim() || null,
+    });
+  }
+
+  return (
+    <FormModal
+      isSaving={false}
+      onClose={onClose}
+      onSubmit={handleSubmit}
+      submitDisabled={!title.trim()}
+      submitLabel={group ? "Übernehmen" : "Kostengruppe hinzufügen"}
+      title={group ? "Kostengruppe bearbeiten" : "Kostengruppe hinzufügen"}
+    >
+      <div className="row g-3">
+        {!group ? (
+          <div className="col-12">
+            <label className="form-label" htmlFor="estimate-group-template">
+              Aus Vorlage KG 400 übernehmen
+            </label>
+            <select
+              className="form-select"
+              defaultValue=""
+              id="estimate-group-template"
+              onChange={(event) => applyTemplate(event.target.value)}
+            >
+              <option value="">– Vorlage wählen –</option>
+              {estimateDefaultGroups.map((template, index) => (
+                <option key={`${template.costGroup}-${template.title}`} value={index}>
+                  {[template.costGroup, template.title].filter(Boolean).join(" ")}
+                </option>
+              ))}
+            </select>
+          </div>
+        ) : null}
+        <div className="col-12 col-md-3">
+          <label className="form-label" htmlFor="estimate-group-cost-group">
+            KG (DIN 276)
+          </label>
+          <input
+            className="form-control"
+            id="estimate-group-cost-group"
+            maxLength={estimateTextLimits.costGroup}
+            onChange={(event) => setCostGroup(event.target.value)}
+            placeholder="z. B. 440"
+            value={costGroup}
+          />
+        </div>
+        <div className="col-12 col-md-9">
+          <label className="form-label" htmlFor="estimate-group-title">
+            Titel
+          </label>
+          <input
+            className="form-control"
+            id="estimate-group-title"
+            maxLength={estimateTextLimits.groupTitle}
+            onChange={(event) => setTitle(event.target.value)}
+            placeholder="z. B. Starkstromanlagen"
+            required
+            value={title}
+          />
+        </div>
+        <div className="col-12">
+          <label className="form-label" htmlFor="estimate-group-editor">
+            Bearbeitet von
+          </label>
+          <input
+            className="form-control"
+            id="estimate-group-editor"
+            maxLength={estimateTextLimits.groupEditor}
+            onChange={(event) => setEditor(event.target.value)}
+            placeholder="Gewerk oder Name (optional)"
+            value={editor}
+          />
+        </div>
+        <div className="col-12">
+          <p className="text-secondary small mb-0">
+            Ohne KG-Nummer (z. B. „Allgemein“) wird die Gruppe im Vergleich mit der
+            detaillierten Bilanz keiner Kostengruppe zugeordnet.
+          </p>
+        </div>
+      </div>
+    </FormModal>
+  );
+}

src/frontend/estimate-balance/estimate-print-header.tsx

@@ -0,0 +1,104 @@
+"use client";
+
+import { useEffect, useState } from "react";
+import { documentLogoUrl, getDocumentBranding } from "../utils/api";
+import type { EstimateBalanceDto, OfficeProfileDto, ProjectDto } from "../types";
+import { formatIsoDateGerman } from "./estimate-balance-format";
+
+interface EstimatePrintHeaderProps {
+  project: ProjectDto;
+  balance: EstimateBalanceDto;
+}
+
+function cssString(value: string) {
+  return JSON.stringify(value.replace(/[<>\r\n]/g, " "));
+}
+
+/**
+ * Print-only title block and page footer of the rough power balance in the
+ * kbp corporate design of the print view (Seitenansicht): logo, blue title,
+ * meta data, "Seite x von y". Hidden on screen.
+ */
+export function EstimatePrintHeader({ project, balance }: EstimatePrintHeaderProps) {
+  const [office, setOffice] = useState<OfficeProfileDto | null>(null);
+  const [hasLogo, setHasLogo] = useState(false);
+  const [logoVersion, setLogoVersion] = useState("");
+
+  useEffect(() => {
+    getDocumentBranding()
+      .then((branding) => {
+        setOffice(branding.office);
+        setHasLogo(Boolean(branding.logo));
+        setLogoVersion(branding.logo ? branding.logo.updatedAtIso : "");
+      })
+      .catch(() => {
+        setOffice(null);
+        setHasLogo(false);
+      });
+  }, []);
+
+  const stand = [balance.name, balance.workStage].filter(Boolean).join(" · ");
+  const date = balance.dateIso ? formatIsoDateGerman(balance.dateIso) : null;
+  const footer = `
+    @page estimate-balance {
+      size: A4 landscape;
+      margin: 10mm 10mm 13mm;
+      @bottom-left { content: ${cssString(`${project.name} · Grobe Leistungsbilanz`)}; font: 7.5pt Arial, sans-serif; color: #6b7280; }
+      @bottom-center { content: ${cssString(`Stand ${stand}${date ? ` · ${date}` : ""}`)}; font: 7.5pt Arial, sans-serif; color: #6b7280; }
+      @bottom-right { content: "Seite " counter(page) " von " counter(pages); font: 7.5pt Arial, sans-serif; color: #6b7280; }
+    }`;
+
+  return (
+    <>
+      <style>{footer}</style>
+      <header className="estimate-print-titleblock" aria-hidden="true">
+        <div className="estimate-print-logo">
+          {hasLogo ? (
+            <img alt="" src={`${documentLogoUrl}?v=${encodeURIComponent(logoVersion)}`} />
+          ) : (
+            <span>{office?.officeName ?? ""}</span>
+          )}
+        </div>
+        <div className="estimate-print-title">
+          <div className="estimate-print-kicker">Grobe Leistungsbilanz · KG 400</div>
+          <div className="estimate-print-heading">
+            <span className="estimate-print-stand">{balance.name}</span>
+            <span className="estimate-print-project">{project.name}</span>
+          </div>
+        </div>
+        <dl className="estimate-print-meta">
+          <div>
+            <dt>Projekt-Nr.</dt>
+            <dd>{project.internalProjectNumber ?? "–"}</dd>
+          </div>
+          <div>
+            <dt>Bauherr</dt>
+            <dd>{project.buildingOwner ?? "–"}</dd>
+          </div>
+          <div>
+            <dt>Anschrift</dt>
+            <dd>{project.siteAddress?.split("\n").join(", ") ?? "–"}</dd>
+          </div>
+        </dl>
+        <dl className="estimate-print-meta is-tinted">
+          <div>
+            <dt>Leistungsphase</dt>
+            <dd>{balance.workStage ?? "–"}</dd>
+          </div>
+          <div>
+            <dt>Datum</dt>
+            <dd>{date ?? "–"}</dd>
+          </div>
+          <div>
+            <dt>Bearbeitung</dt>
+            <dd>{project.projectEditor ?? "–"}</dd>
+          </div>
+          <div>
+            <dt>Büro</dt>
+            <dd>{office?.officeName ?? "–"}</dd>
+          </div>
+        </dl>
+      </header>
+    </>
+  );
+}

src/frontend/types.ts

@@ -535,3 +535,34 @@ export interface CreateCircuitDeviceRowInputDto {
 }
 
 import type { ProjectDeviceSyncField } from "../shared/constants/project-device-sync-fields";
+
+// ── Grobe Leistungsbilanz (LPH 2/3) ─────────────────────────────────────
+// The document shapes are shared with the API; see
+// src/shared/estimate-balance/estimate-balance.ts.
+import type {
+  EstimateBalanceSnapshot,
+  EstimateComparison,
+} from "../shared/estimate-balance/estimate-balance";
+
+export type EstimateBalanceDto = EstimateBalanceSnapshot;
+export type EstimateComparisonDto = EstimateComparison;
+
+export type EstimateBalanceTemplate = "kg400" | "empty" | "copy";
+
+export interface CreateEstimateBalanceInput {
+  name: string;
+  workStage?: string | null;
+  dateIso?: string | null;
+  template: EstimateBalanceTemplate;
+  /** Required for template "copy". */
+  copyFromBalanceId?: string;
+}
+
+export interface EstimateBalanceCommandResultDto extends ProjectCommandResultDto {
+  balance: EstimateBalanceDto;
+}
+
+/** PUT result: either a new revision or an unchanged document. */
+export type EstimateBalanceUpdateResultDto =
+  | EstimateBalanceCommandResultDto
+  | { unchanged: true; balance: EstimateBalanceDto };

src/frontend/utils/api.ts

@@ -38,6 +38,11 @@ import type {
   ExternalInitialImportPlanDto,
   ApplyExternalInitialImportInput,
   ExternalInitialImportResultDto,
+  CreateEstimateBalanceInput,
+  EstimateBalanceCommandResultDto,
+  EstimateBalanceDto,
+  EstimateBalanceUpdateResultDto,
+  EstimateComparisonDto,
 } from "../types";
 import type { ExternalCsvConfiguration } from "../../external-model/csv/external-csv-contracts";
 import type { ProjectDeviceSyncField } from "../../shared/constants/project-device-sync-fields";
@@ -87,6 +92,30 @@ import type {
   CircuitGroupSubtreeSnapshot,
 } from "../../domain/models/circuit-group-subtree-snapshot.model";
 
+/**
+ * Error of a failed API request. The message stays the server's German
+ * error text; status and optional error code allow callers to react to
+ * specific failures such as a revision conflict (409).
+ */
+export class ApiRequestError extends Error {
+  readonly status: number;
+  readonly code: string | null;
+
+  constructor(message: string, status: number, code: string | null = null) {
+    super(message);
+    this.name = "ApiRequestError";
+    this.status = status;
+    this.code = code;
+  }
+}
+
+export function isRevisionConflictError(error: unknown) {
+  return (
+    error instanceof ApiRequestError &&
+    (error.status === 409 || error.code === "PROJECT_REVISION_CONFLICT")
+  );
+}
+
 async function request<T>(url: string, init?: RequestInit): Promise<T> {
   const response = await fetch(url, {
     ...init,
@@ -99,15 +128,23 @@ async function request<T>(url: string, init?: RequestInit): Promise<T> {
 
   if (!response.ok) {
     let details = await response.text();
+    let code: string | null = null;
     try {
-      const parsed = JSON.parse(details) as { error?: unknown };
+      const parsed = JSON.parse(details) as { error?: unknown; code?: unknown };
       if (typeof parsed.error === "string") {
         details = parsed.error;
       }
+      if (typeof parsed.code === "string") {
+        code = parsed.code;
+      }
     } catch {
       // Keep non-JSON error responses unchanged.
     }
-    throw new Error(details || `Anfrage fehlgeschlagen (Status ${response.status})`);
+    throw new ApiRequestError(
+      details || `Anfrage fehlgeschlagen (Status ${response.status})`,
+      response.status,
+      code
+    );
   }
 
   if (response.status === 204) {
@@ -1135,3 +1172,66 @@ export function disconnectProjectDeviceRows(
     }
   );
 }
+
+// ── Grobe Leistungsbilanz (LPH 2/3) ─────────────────────────────────────
+
+function estimateBalancesUrl(projectId: string, balanceId?: string) {
+  const base = `/api/projects/${projectId}/estimate-balances`;
+  return balanceId ? `${base}/${balanceId}` : base;
+}
+
+export function listEstimateBalances(projectId: string) {
+  return request<EstimateBalanceDto[]>(estimateBalancesUrl(projectId));
+}
+
+export function getEstimateBalance(projectId: string, balanceId: string) {
+  return request<EstimateBalanceDto>(estimateBalancesUrl(projectId, balanceId));
+}
+
+export function createEstimateBalance(
+  projectId: string,
+  input: CreateEstimateBalanceInput,
+  expectedRevision: number
+) {
+  return request<EstimateBalanceCommandResultDto>(estimateBalancesUrl(projectId), {
+    method: "POST",
+    body: JSON.stringify({ ...input, expectedRevision }),
+  });
+}
+
+/**
+ * Saves the complete target document. `keepalive` lets the request outlive
+ * the page, e.g. for the last autosave while the tab is being closed.
+ */
+export function updateEstimateBalance(
+  projectId: string,
+  balance: EstimateBalanceDto,
+  expectedRevision: number,
+  options: { keepalive?: boolean } = {}
+) {
+  return request<EstimateBalanceUpdateResultDto>(
+    estimateBalancesUrl(projectId, balance.id),
+    {
+      method: "PUT",
+      body: JSON.stringify({ expectedRevision, balance }),
+      ...(options.keepalive ? { keepalive: true } : {}),
+    }
+  );
+}
+
+export function deleteEstimateBalance(
+  projectId: string,
+  balanceId: string,
+  expectedRevision: number
+) {
+  return request<ProjectCommandResultDto>(estimateBalancesUrl(projectId, balanceId), {
+    method: "DELETE",
+    body: JSON.stringify({ expectedRevision }),
+  });
+}
+
+export function getEstimateComparison(projectId: string, balanceId: string) {
+  return request<EstimateComparisonDto>(
+    `${estimateBalancesUrl(projectId, balanceId)}/comparison`
+  );
+}

src/frontend/utils/project-version-history.ts

@@ -68,6 +68,9 @@ const commandTypeLabels: Record<string, string> = {
   "external-object.unassign-and-delete-created-row":
     "Externes Objekt aus erzeugter Gerätezeile gelöst",
   "external-object.update-row-assignment": "Externe Objektzuordnung geändert",
+  "estimate-balance.insert": "Grobe Leistungsbilanz angelegt",
+  "estimate-balance.update": "Grobe Leistungsbilanz bearbeitet",
+  "estimate-balance.delete": "Grobe Leistungsbilanz entfernt",
 };
 
 export function getProjectRevisionSourceLabel(

src/server/composition/application-repositories.ts

@@ -7,6 +7,7 @@ import { CircuitProtectionDeviceRepository } from "../../db/repositories/circuit
 import { DistributionBoardComponentRepository } from "../../db/repositories/distribution-board-component.repository.js";
 import { DistributionBoardRepository } from "../../db/repositories/distribution-board.repository.js";
 import { BuildingRepository } from "../../db/repositories/building.repository.js";
+import { EstimateBalanceRepository } from "../../db/repositories/estimate-balance.repository.js";
 import { FloorRepository } from "../../db/repositories/floor.repository.js";
 import { GlobalDeviceRepository } from "../../db/repositories/global-device.repository.js";
 import { ProjectDeviceRepository } from "../../db/repositories/project-device.repository.js";
@@ -28,6 +29,7 @@ export const distributionBoardComponentRepository =
 export const distributionBoardRepository =
   new DistributionBoardRepository(db);
 export const buildingRepository = new BuildingRepository(db);
+export const estimateBalanceRepository = new EstimateBalanceRepository(db);
 export const floorRepository = new FloorRepository(db);
 export const globalDeviceRepository = new GlobalDeviceRepository(db);
 export const projectDeviceRepository = new ProjectDeviceRepository(db);

src/server/composition/project-command-stores.ts

@@ -27,6 +27,7 @@ import { ExternalInitialImportProjectCommandRepository } from "../../db/reposito
 import { ExternalObjectRowAssignmentProjectCommandRepository } from "../../db/repositories/external-object-row-assignment-project-command.repository.js";
 import { ExternalObjectNewRowProjectCommandRepository } from "../../db/repositories/external-object-new-row-project-command.repository.js";
 import { ExternalObjectNewCircuitProjectCommandRepository } from "../../db/repositories/external-object-new-circuit-project-command.repository.js";
+import { EstimateBalanceProjectCommandRepository } from "../../db/repositories/estimate-balance-project-command.repository.js";
 
 export const circuitProjectCommandStore = new CircuitProjectCommandRepository(db);
 export const circuitDeviceRowProjectCommandStore =
@@ -80,6 +81,8 @@ export const externalObjectNewRowProjectCommandStore =
   new ExternalObjectNewRowProjectCommandRepository(db);
 export const externalObjectNewCircuitProjectCommandStore =
   new ExternalObjectNewCircuitProjectCommandRepository(db);
+export const estimateBalanceProjectCommandStore =
+  new EstimateBalanceProjectCommandRepository(db);
 export const projectCommandService = new ProjectCommandService(
   circuitProjectCommandStore,
   circuitDeviceRowProjectCommandStore,
@@ -107,5 +110,6 @@ export const projectCommandService = new ProjectCommandService(
   externalInitialImportProjectCommandStore,
   externalObjectRowAssignmentProjectCommandStore,
   externalObjectNewRowProjectCommandStore,
-  externalObjectNewCircuitProjectCommandStore
+  externalObjectNewCircuitProjectCommandStore,
+  estimateBalanceProjectCommandStore
 );

src/server/controllers/estimate-balance.controller.ts

@@ -0,0 +1,180 @@
+import type { Request, Response } from "express";
+import { ZodError } from "zod";
+import {
+  createEstimateBalanceDeleteProjectCommand,
+  createEstimateBalanceInsertProjectCommand,
+  createEstimateBalanceSnapshot,
+  createEstimateBalanceUpdateProjectCommand,
+  parseEstimateBalanceSnapshot,
+  sameEstimateBalance,
+} from "../../estimate-balance/domain/estimate-balance-command.model.js";
+import {
+  createEstimateBalanceRequestSchema,
+  deleteEstimateBalanceRequestSchema,
+  updateEstimateBalanceRequestSchema,
+} from "../../estimate-balance/api/estimate-balance-request.schemas.js";
+import { compareEstimateWithDetailed } from "../../shared/estimate-balance/estimate-balance.js";
+import { estimateBalanceRepository } from "../composition/application-repositories.js";
+import { projectCommandService } from "../composition/project-command-stores.js";
+import { respondWithProjectCommandError } from "./project-command.controller.js";
+
+function params(req: Request) {
+  const { projectId, balanceId } = req.params;
+  return {
+    projectId: typeof projectId === "string" ? projectId : null,
+    balanceId: typeof balanceId === "string" ? balanceId : null,
+  };
+}
+
+export function listEstimateBalances(req: Request, res: Response) {
+  const { projectId } = params(req);
+  if (!projectId) {
+    return res.status(400).json({ error: "Ungültige Projekt-ID." });
+  }
+  return res.json(estimateBalanceRepository.listByProject(projectId));
+}
+
+export function getEstimateBalance(req: Request, res: Response) {
+  const { projectId, balanceId } = params(req);
+  if (!projectId || !balanceId) {
+    return res.status(400).json({ error: "Ungültige Parameter." });
+  }
+  const balance = estimateBalanceRepository.findById(projectId, balanceId);
+  if (!balance) {
+    return res.status(404).json({ error: "Grobe Leistungsbilanz nicht gefunden." });
+  }
+  return res.json(balance);
+}
+
+export function createEstimateBalance(req: Request, res: Response) {
+  const { projectId } = params(req);
+  if (!projectId) {
+    return res.status(400).json({ error: "Ungültige Projekt-ID." });
+  }
+  const parsed = createEstimateBalanceRequestSchema.safeParse(req.body);
+  if (!parsed.success) {
+    return res.status(400).json({ error: parsed.error.flatten() });
+  }
+  let template: Parameters<typeof createEstimateBalanceSnapshot>[0]["template"] =
+    parsed.data.template === "copy" ? "empty" : parsed.data.template;
+  if (parsed.data.template === "copy") {
+    const source = estimateBalanceRepository.findById(
+      projectId,
+      parsed.data.copyFromBalanceId!
+    );
+    if (!source) {
+      return res
+        .status(404)
+        .json({ error: "Der zu kopierende Stand wurde nicht gefunden." });
+    }
+    template = { copyFrom: source };
+  }
+  try {
+    const balance = createEstimateBalanceSnapshot({
+      projectId,
+      name: parsed.data.name,
+      workStage: parsed.data.workStage ?? null,
+      dateIso: parsed.data.dateIso ?? null,
+      sortOrder: estimateBalanceRepository.nextSortOrder(projectId),
+      template,
+    });
+    const result = projectCommandService.executeUser({
+      projectId,
+      expectedRevision: parsed.data.expectedRevision,
+      description: "Grobe Leistungsbilanz anlegen",
+      command: createEstimateBalanceInsertProjectCommand(balance),
+    });
+    return res.status(201).json({ ...result, balance });
+  } catch (error) {
+    return respondWithProjectCommandError(error, res);
+  }
+}
+
+export function updateEstimateBalance(req: Request, res: Response) {
+  const { projectId, balanceId } = params(req);
+  if (!projectId || !balanceId) {
+    return res.status(400).json({ error: "Ungültige Parameter." });
+  }
+  const parsed = updateEstimateBalanceRequestSchema.safeParse(req.body);
+  if (!parsed.success) {
+    return res.status(400).json({ error: parsed.error.flatten() });
+  }
+  let target;
+  try {
+    target = parseEstimateBalanceSnapshot(parsed.data.balance);
+  } catch (error) {
+    return res.status(400).json({
+      error: "Die grobe Leistungsbilanz enthält ungültige Werte.",
+      issues: error instanceof ZodError ? error.issues : undefined,
+    });
+  }
+  if (target.id !== balanceId || target.projectId !== projectId) {
+    return res
+      .status(400)
+      .json({ error: "Die Bilanz gehört nicht zu diesem Projekt oder dieser Adresse." });
+  }
+  const current = estimateBalanceRepository.findById(projectId, balanceId);
+  if (!current) {
+    return res.status(404).json({ error: "Grobe Leistungsbilanz nicht gefunden." });
+  }
+  if (sameEstimateBalance(current, target)) {
+    return res.json({ unchanged: true, balance: current });
+  }
+  try {
+    const result = projectCommandService.executeUser({
+      projectId,
+      expectedRevision: parsed.data.expectedRevision,
+      description: "Grobe Leistungsbilanz bearbeiten",
+      command: createEstimateBalanceUpdateProjectCommand(current, target),
+    });
+    return res.json({
+      ...result,
+      balance: estimateBalanceRepository.findById(projectId, balanceId),
+    });
+  } catch (error) {
+    return respondWithProjectCommandError(error, res);
+  }
+}
+
+export function deleteEstimateBalance(req: Request, res: Response) {
+  const { projectId, balanceId } = params(req);
+  if (!projectId || !balanceId) {
+    return res.status(400).json({ error: "Ungültige Parameter." });
+  }
+  const parsed = deleteEstimateBalanceRequestSchema.safeParse(req.body);
+  if (!parsed.success) {
+    return res.status(400).json({ error: parsed.error.flatten() });
+  }
+  const current = estimateBalanceRepository.findById(projectId, balanceId);
+  if (!current) {
+    return res.status(404).json({ error: "Grobe Leistungsbilanz nicht gefunden." });
+  }
+  try {
+    const result = projectCommandService.executeUser({
+      projectId,
+      expectedRevision: parsed.data.expectedRevision,
+      description: "Grobe Leistungsbilanz löschen",
+      command: createEstimateBalanceDeleteProjectCommand(current),
+    });
+    return res.json(result);
+  } catch (error) {
+    return respondWithProjectCommandError(error, res);
+  }
+}
+
+export function getEstimateComparison(req: Request, res: Response) {
+  const { projectId, balanceId } = params(req);
+  if (!projectId || !balanceId) {
+    return res.status(400).json({ error: "Ungültige Parameter." });
+  }
+  const balance = estimateBalanceRepository.findById(projectId, balanceId);
+  if (!balance) {
+    return res.status(404).json({ error: "Grobe Leistungsbilanz nicht gefunden." });
+  }
+  return res.json(
+    compareEstimateWithDetailed(
+      balance,
+      estimateBalanceRepository.listDetailedDeviceRowPower(projectId)
+    )
+  );
+}

src/server/routes/project.routes.ts

@@ -21,6 +21,14 @@ import {
 } from "../controllers/building.controller.js";
 import { createFloor, deleteFloor, listFloorsByProject, updateFloor } from "../controllers/floor.controller.js";
 import { createRoom, deleteRoom, listRoomsByProject, updateRoom } from "../controllers/room.controller.js";
+import {
+  createEstimateBalance,
+  deleteEstimateBalance,
+  getEstimateBalance,
+  getEstimateComparison,
+  listEstimateBalances,
+  updateEstimateBalance,
+} from "../controllers/estimate-balance.controller.js";
 import { getCircuitTree } from "../controllers/circuit-tree.controller.js";
 import { getNextCircuitIdentifier } from "../controllers/circuit.controller.js";
 import {
@@ -118,3 +126,12 @@ projectRouter.get("/:projectId/rooms", listRoomsByProject);
 projectRouter.post("/:projectId/rooms", createRoom);
 projectRouter.put("/:projectId/rooms/:roomId", updateRoom);
 projectRouter.delete("/:projectId/rooms/:roomId", deleteRoom);
+projectRouter.get("/:projectId/estimate-balances", listEstimateBalances);
+projectRouter.post("/:projectId/estimate-balances", createEstimateBalance);
+projectRouter.get("/:projectId/estimate-balances/:balanceId", getEstimateBalance);
+projectRouter.put("/:projectId/estimate-balances/:balanceId", updateEstimateBalance);
+projectRouter.delete("/:projectId/estimate-balances/:balanceId", deleteEstimateBalance);
+projectRouter.get(
+  "/:projectId/estimate-balances/:balanceId/comparison",
+  getEstimateComparison
+);

src/shared/estimate-balance/estimate-balance.ts

@@ -0,0 +1,314 @@
+/**
+ * Grobe Leistungsbilanz (LPH 2/3): shared data shapes and pure calculation.
+ *
+ * Used by the API (validation, comparison) and by the frontend (live totals),
+ * so this file has no imports: Turbopack resolves frontend imports without
+ * the `.js` suffix the API build needs.
+ */
+
+export type EstimateRowUnit = "piece" | "area";
+export type EstimateRowConnection = "fixed" | "socket";
+
+export interface EstimateRowSnapshot {
+  id: string;
+  sortOrder: number;
+  /** Versorgung, e.g. "ELT" or "MSR" (free text). */
+  supply: string | null;
+  /** Verbraucher / Fläche. May be empty while a row is being typed. */
+  name: string;
+  /** Anzahl (unit "piece") or area in m² (unit "area"). */
+  quantity: number;
+  unit: EstimateRowUnit;
+  connection: EstimateRowConnection | null;
+  /** W per piece or W/m². */
+  powerPerUnitW: number;
+  simultaneityFactor: number;
+  cosPhi: number;
+  /** Also needed on the safety power supply (SV). */
+  safetySupply: boolean;
+  remark: string | null;
+}
+
+export interface EstimateGroupSnapshot {
+  id: string;
+  /** DIN 276 cost group, e.g. "410" or "434"; empty for "Allgemein". */
+  costGroup: string;
+  title: string;
+  /** Trade or person responsible for the entries ("bearbeitet von"). */
+  editor: string | null;
+  sortOrder: number;
+  rows: EstimateRowSnapshot[];
+}
+
+export interface EstimateBalanceSnapshot {
+  id: string;
+  projectId: string;
+  /** Stand, e.g. "Vorplanung" or "Entwurfsplanung". */
+  name: string;
+  workStage: string | null;
+  /** ISO date YYYY-MM-DD. */
+  dateIso: string | null;
+  reserveAvPercent: number;
+  reserveSvPercent: number;
+  sortOrder: number;
+  groups: EstimateGroupSnapshot[];
+}
+
+/** Default structure of the office template "Leistungsbilanz - KG400". */
+export const estimateDefaultGroups: ReadonlyArray<{ costGroup: string; title: string }> = [
+  { costGroup: "410", title: "Sanitärtechnik" },
+  { costGroup: "420", title: "Wärmeversorgung" },
+  { costGroup: "430", title: "Lufttechnische Anlagen" },
+  { costGroup: "434", title: "Kälteanlagen" },
+  { costGroup: "440", title: "Starkstromanlagen" },
+  { costGroup: "450", title: "Schwachstromanlagen" },
+  { costGroup: "460", title: "Fördertechnik" },
+  { costGroup: "470", title: "Nutzungsspezifische Anlagen" },
+  { costGroup: "480", title: "Gebäudeautomation" },
+  { costGroup: "", title: "Allgemein" },
+];
+
+export const estimateRowUnitLabels: Record<EstimateRowUnit, string> = {
+  piece: "St.",
+  area: "m²",
+};
+
+export const estimateRowConnectionLabels: Record<EstimateRowConnection, string> = {
+  fixed: "Fest",
+  socket: "Steckd.",
+};
+
+export interface EstimatePower {
+  kw: number;
+  kva: number;
+}
+
+export interface EstimateRowResult {
+  av: EstimatePower;
+  sv: EstimatePower;
+}
+
+export interface EstimateGroupResult {
+  groupId: string;
+  av: EstimatePower;
+  sv: EstimatePower;
+}
+
+export interface EstimateBalanceResult {
+  groups: EstimateGroupResult[];
+  total: { av: EstimatePower; sv: EstimatePower };
+  reserve: { av: EstimatePower; sv: EstimatePower };
+  withReserve: { av: EstimatePower; sv: EstimatePower };
+  /** Maximum current of the three-phase supply in A (S / (√3 · U)). */
+  maxCurrentA: { av: number; sv: number };
+}
+
+/**
+ * Rounds a calculated value for display like the spreadsheet does: binary
+ * floating point stores 40.175 as 40.17499…, so the scaled value is first
+ * cut to 6 decimals and only then rounded half away from zero
+ * (40.175 -> 40.18, -1.825 -> -1.83).
+ */
+export function roundEstimateValue(value: number, digits = 2): number {
+  const factor = 10 ** digits;
+  const scaled = Number((Math.abs(value) * factor).toFixed(6));
+  return (Math.sign(value) * Math.round(scaled)) / factor;
+}
+
+const zeroPower = (): EstimatePower => ({ kw: 0, kva: 0 });
+
+function addPower(left: EstimatePower, right: EstimatePower): EstimatePower {
+  return { kw: left.kw + right.kw, kva: left.kva + right.kva };
+}
+
+function scalePower(power: EstimatePower, factor: number): EstimatePower {
+  return { kw: power.kw * factor, kva: power.kva * factor };
+}
+
+/**
+ * Required power of one row: P = quantity · power per unit · GLF, S = P / cos φ.
+ * AV covers every consumer (normal supply); SV additionally lists the rows
+ * that must also be supplied by the safety power supply.
+ */
+export function calculateEstimateRow(
+  row: Pick<
+    EstimateRowSnapshot,
+    "quantity" | "powerPerUnitW" | "simultaneityFactor" | "cosPhi" | "safetySupply"
+  >
+): EstimateRowResult {
+  const kw = (row.quantity * row.powerPerUnitW * row.simultaneityFactor) / 1000;
+  const kva = row.cosPhi > 0 ? kw / row.cosPhi : 0;
+  const av = { kw, kva };
+  return { av, sv: row.safetySupply ? { ...av } : zeroPower() };
+}
+
+export function calculateEstimateBalance(
+  balance: Pick<EstimateBalanceSnapshot, "groups" | "reserveAvPercent" | "reserveSvPercent">,
+  threePhaseVoltageV: number
+): EstimateBalanceResult {
+  const groups = balance.groups.map((group) =>
+    group.rows.reduce<EstimateGroupResult>(
+      (sum, row) => {
+        const result = calculateEstimateRow(row);
+        return {
+          groupId: group.id,
+          av: addPower(sum.av, result.av),
+          sv: addPower(sum.sv, result.sv),
+        };
+      },
+      { groupId: group.id, av: zeroPower(), sv: zeroPower() }
+    )
+  );
+  const total = groups.reduce(
+    (sum, group) => ({ av: addPower(sum.av, group.av), sv: addPower(sum.sv, group.sv) }),
+    { av: zeroPower(), sv: zeroPower() }
+  );
+  const reserve = {
+    av: scalePower(total.av, balance.reserveAvPercent / 100),
+    sv: scalePower(total.sv, balance.reserveSvPercent / 100),
+  };
+  const withReserve = {
+    av: addPower(total.av, reserve.av),
+    sv: addPower(total.sv, reserve.sv),
+  };
+  const currentFactor =
+    threePhaseVoltageV > 0 ? 1000 / (Math.sqrt(3) * threePhaseVoltageV) : 0;
+  return {
+    groups,
+    total,
+    reserve,
+    withReserve,
+    maxCurrentA: {
+      av: withReserve.av.kva * currentFactor,
+      sv: withReserve.sv.kva * currentFactor,
+    },
+  };
+}
+
+/**
+ * Assigns a detailed cost group (e.g. "444" or "440.1") to the best matching
+ * estimate group: a group code with trailing zeros removed is a prefix
+ * ("430" -> "43", "434" -> "434"); the longest prefix wins. Returns null when
+ * no group matches.
+ */
+export function matchEstimateCostGroup(
+  detailedCostGroup: string | null,
+  groupCostGroups: readonly string[]
+): string | null {
+  const digits = (detailedCostGroup ?? "").replace(/\D/g, "");
+  if (!digits) {
+    return null;
+  }
+  let best: { code: string; length: number } | null = null;
+  for (const code of groupCostGroups) {
+    const codeDigits = code.replace(/\D/g, "");
+    const prefix = codeDigits.replace(/0+$/, "");
+    if (!prefix || !digits.startsWith(prefix)) {
+      continue;
+    }
+    if (!best || prefix.length > best.length) {
+      best = { code, length: prefix.length };
+    }
+  }
+  return best?.code ?? null;
+}
+
+export interface EstimateComparisonGroup {
+  groupId: string;
+  costGroup: string;
+  title: string;
+  estimatedAv: EstimatePower;
+  detailed: EstimatePower;
+  detailedRowCount: number;
+  deltaKw: number;
+  /** Relative deviation of the detailed value from the estimate, null without estimate. */
+  deltaPercent: number | null;
+}
+
+export interface EstimateComparison {
+  groups: EstimateComparisonGroup[];
+  unassigned: EstimatePower & { rowCount: number };
+  total: {
+    estimatedAv: EstimatePower;
+    detailed: EstimatePower;
+    deltaKw: number;
+    deltaPercent: number | null;
+  };
+}
+
+export interface DetailedDeviceRowPower {
+  costGroup: string | null;
+  /** Total power of the device row in kW (quantity · power · device GZF). */
+  kw: number;
+  cosPhi: number | null;
+}
+
+function delta(estimated: number, detailed: number) {
+  return {
+    deltaKw: detailed - estimated,
+    deltaPercent: estimated > 0 ? ((detailed - estimated) / estimated) * 100 : null,
+  };
+}
+
+/**
+ * Compares the estimate per cost group with the detailed device rows of all
+ * circuit lists. The distribution-board simultaneity factor is not applied
+ * on either side; a missing cos φ counts as 1.
+ */
+export function compareEstimateWithDetailed(
+  balance: Pick<EstimateBalanceSnapshot, "groups" | "reserveAvPercent" | "reserveSvPercent">,
+  detailedRows: readonly DetailedDeviceRowPower[]
+): EstimateComparison {
+  const estimate = calculateEstimateBalance(balance, 0);
+  const codes = balance.groups.map((group) => group.costGroup).filter(Boolean);
+  const detailedByCode = new Map<string, EstimatePower & { rowCount: number }>();
+  const unassigned = { kw: 0, kva: 0, rowCount: 0 };
+  for (const row of detailedRows) {
+    const kva = row.cosPhi && row.cosPhi > 0 ? row.kw / row.cosPhi : row.kw;
+    const code = matchEstimateCostGroup(row.costGroup, codes);
+    const target =
+      code === null
+        ? unassigned
+        : detailedByCode.get(code) ??
+          detailedByCode.set(code, { kw: 0, kva: 0, rowCount: 0 }).get(code)!;
+    target.kw += row.kw;
+    target.kva += kva;
+    target.rowCount += 1;
+  }
+  // A cost group code can appear in several groups; the detailed value is
+  // shown once, on the first group with that code.
+  const shownCodes = new Set<string>();
+  const groups = balance.groups.map((group, index) => {
+    const estimatedAv = estimate.groups[index]!.av;
+    const detailedEntry =
+      group.costGroup && !shownCodes.has(group.costGroup)
+        ? detailedByCode.get(group.costGroup)
+        : undefined;
+    if (group.costGroup) {
+      shownCodes.add(group.costGroup);
+    }
+    const detailed = { kw: detailedEntry?.kw ?? 0, kva: detailedEntry?.kva ?? 0 };
+    return {
+      groupId: group.id,
+      costGroup: group.costGroup,
+      title: group.title,
+      estimatedAv,
+      detailed,
+      detailedRowCount: detailedEntry?.rowCount ?? 0,
+      ...delta(estimatedAv.kw, detailed.kw),
+    };
+  });
+  const detailedTotal = groups.reduce(
+    (sum, group) => addPower(sum, group.detailed),
+    { kw: unassigned.kw, kva: unassigned.kva }
+  );
+  return {
+    groups,
+    unassigned,
+    total: {
+      estimatedAv: estimate.total.av,
+      detailed: detailedTotal,
+      ...delta(estimate.total.av.kw, detailedTotal.kw),
+    },
+  };
+}

tests/estimate-balance-frontend.test.ts

@@ -0,0 +1,432 @@
+import assert from "node:assert/strict";
+import { describe, it } from "node:test";
+import type { EstimateBalanceSnapshot } from "../src/shared/estimate-balance/estimate-balance.js";
+import {
+  addEstimateGroup,
+  addEstimateRow,
+  createCopyName,
+  createEstimateRow,
+  estimateBalanceFingerprint,
+  moveEstimateGroup,
+  moveEstimateRow,
+  normalizeEstimateSortOrder,
+  removeEstimateGroup,
+  removeEstimateRow,
+  toSaveableEstimateBalance,
+  updateEstimateGroup,
+  updateEstimateRow,
+  validateEstimateBalance,
+} from "../src/frontend/estimate-balance/estimate-balance-document.js";
+import {
+  estimateNumberRanges,
+  formatAmpere,
+  formatDecimalInput,
+  formatDeltaPercent,
+  formatIsoDateGerman,
+  formatKw,
+  formatSignedKw,
+  getTodayIsoDate,
+  parseGermanDecimal,
+} from "../src/frontend/estimate-balance/estimate-balance-format.js";
+import {
+  ApiRequestError,
+  createEstimateBalance,
+  deleteEstimateBalance,
+  getEstimateBalance,
+  getEstimateComparison,
+  isRevisionConflictError,
+  listEstimateBalances,
+  updateEstimateBalance,
+} from "../src/frontend/utils/api.js";
+
+function sequentialIds(prefix = "id") {
+  let next = 0;
+  return () => `${prefix}-${++next}`;
+}
+
+function sampleBalance(): EstimateBalanceSnapshot {
+  return {
+    id: "balance-1",
+    projectId: "project-1",
+    name: "Entwurfsplanung",
+    workStage: "LPH 3",
+    dateIso: "2026-09-26",
+    reserveAvPercent: 20,
+    reserveSvPercent: 10,
+    sortOrder: 0,
+    groups: [
+      {
+        id: "group-410",
+        costGroup: "410",
+        title: "Sanitärtechnik",
+        editor: null,
+        sortOrder: 0,
+        rows: [
+          { ...createEstimateRow(0, () => "row-a"), name: "Hebeanlage", powerPerUnitW: 1200 },
+          { ...createEstimateRow(1, () => "row-b"), name: "Durchlauferhitzer" },
+        ],
+      },
+      {
+        id: "group-440",
+        costGroup: "440",
+        title: "Starkstromanlagen",
+        editor: "ELT",
+        sortOrder: 1,
+        rows: [],
+      },
+    ],
+  };
+}
+
+describe("estimate balance number input", () => {
+  it("accepts a comma as decimal separator", () => {
+    assert.deepEqual(parseGermanDecimal("0,8"), { ok: true, value: 0.8 });
+    assert.deepEqual(parseGermanDecimal(" 1200 "), { ok: true, value: 1200 });
+    assert.deepEqual(parseGermanDecimal(",5"), { ok: true, value: 0.5 });
+    assert.deepEqual(parseGermanDecimal("3,"), { ok: true, value: 3 });
+  });
+
+  it("rejects dots, empty input and garbage", () => {
+    for (const text of ["0.8", "1.200", "", "  ", "abc", "1,2,3", "1e3", "--1"]) {
+      assert.equal(parseGermanDecimal(text).ok, false, text);
+    }
+    const dot = parseGermanDecimal("0.8");
+    assert.equal(dot.ok === false && dot.error.includes("Komma"), true);
+  });
+
+  it("checks the server ranges of the document fields", () => {
+    assert.equal(parseGermanDecimal("-1", estimateNumberRanges.quantity).ok, false);
+    assert.equal(parseGermanDecimal("0", estimateNumberRanges.quantity).ok, true);
+    assert.equal(parseGermanDecimal("1,1", estimateNumberRanges.simultaneityFactor).ok, false);
+    assert.equal(parseGermanDecimal("1", estimateNumberRanges.simultaneityFactor).ok, true);
+    assert.equal(parseGermanDecimal("0", estimateNumberRanges.cosPhi).ok, false);
+    assert.equal(parseGermanDecimal("0,01", estimateNumberRanges.cosPhi).ok, true);
+    assert.equal(parseGermanDecimal("101", estimateNumberRanges.reservePercent).ok, false);
+  });
+
+  it("formats input text so it parses back unchanged", () => {
+    assert.equal(formatDecimalInput(1200), "1200");
+    assert.equal(formatDecimalInput(0.8), "0,8");
+    const parsed = parseGermanDecimal(formatDecimalInput(12345.678));
+    assert.deepEqual(parsed, { ok: true, value: 12345.678 });
+  });
+});
+
+describe("estimate balance display format", () => {
+  it("rounds half away from zero like Excel", () => {
+    assert.equal(formatKw(40.175), "40,18");
+    assert.equal(formatKw(30.24), "30,24");
+    assert.equal(formatKw(1234.5), "1.234,50");
+    assert.equal(formatKw(-0.001), "0,00");
+    assert.equal(formatAmpere(57.75), "57,75");
+    assert.equal(formatAmpere(235.749), "235,75");
+  });
+
+  it("shows signed deltas and percentages", () => {
+    assert.equal(formatSignedKw(1.5), "+1,50");
+    assert.equal(formatSignedKw(-1.825), "-1,83");
+    assert.equal(formatSignedKw(0.001), "0,00");
+    assert.equal(formatDeltaPercent(12.34), "+12,3 %");
+    assert.equal(formatDeltaPercent(-5), "-5,0 %");
+    assert.equal(formatDeltaPercent(null), "–");
+  });
+
+  it("formats dates", () => {
+    assert.equal(formatIsoDateGerman("2026-09-26"), "26.09.2026");
+    assert.equal(formatIsoDateGerman(null), "–");
+    assert.equal(getTodayIsoDate(new Date(2026, 0, 5, 23, 30)), "2026-01-05");
+  });
+});
+
+describe("estimate balance document editing", () => {
+  it("adds rows at the end or after a row with continuous sort orders", () => {
+    const createId = sequentialIds("new");
+    const appended = addEstimateRow(sampleBalance(), "group-410", { createId });
+    assert.equal(appended.rowId, "new-1");
+    assert.deepEqual(
+      appended.balance.groups[0]!.rows.map((row) => [row.id, row.sortOrder]),
+      [["row-a", 0], ["row-b", 1], ["new-1", 2]]
+    );
+    const inserted = addEstimateRow(sampleBalance(), "group-410", {
+      afterRowId: "row-a",
+      createId,
+    });
+    assert.deepEqual(
+      inserted.balance.groups[0]!.rows.map((row) => [row.id, row.sortOrder]),
+      [["row-a", 0], ["new-2", 1], ["row-b", 2]]
+    );
+    const unknownGroup = addEstimateRow(sampleBalance(), "missing", { createId });
+    assert.equal(unknownGroup.rowId, null);
+  });
+
+  it("creates rows with neutral defaults", () => {
+    const row = createEstimateRow(3, () => "row-x");
+    assert.deepEqual(row, {
+      id: "row-x",
+      sortOrder: 3,
+      supply: null,
+      name: "",
+      quantity: 1,
+      unit: "piece",
+      connection: null,
+      powerPerUnitW: 0,
+      simultaneityFactor: 1,
+      cosPhi: 1,
+      safetySupply: false,
+      remark: null,
+    });
+  });
+
+  it("updates, removes and moves rows without touching the input", () => {
+    const original = sampleBalance();
+    const updated = updateEstimateRow(original, "group-410", "row-b", {
+      quantity: 3,
+      safetySupply: true,
+    });
+    assert.equal(updated.groups[0]!.rows[1]!.quantity, 3);
+    assert.equal(updated.groups[0]!.rows[1]!.safetySupply, true);
+    assert.equal(original.groups[0]!.rows[1]!.quantity, 1);
+
+    const removed = removeEstimateRow(original, "group-410", "row-a");
+    assert.deepEqual(
+      removed.groups[0]!.rows.map((row) => [row.id, row.sortOrder]),
+      [["row-b", 0]]
+    );
+
+    const moved = moveEstimateRow(original, "group-410", "row-b", -1);
+    assert.deepEqual(
+      moved.groups[0]!.rows.map((row) => [row.id, row.sortOrder]),
+      [["row-b", 0], ["row-a", 1]]
+    );
+    assert.equal(moveEstimateRow(original, "group-410", "row-a", -1), original);
+  });
+
+  it("adds, edits, moves and removes groups", () => {
+    const added = addEstimateGroup(
+      sampleBalance(),
+      { costGroup: "480", title: "Gebäudeautomation" },
+      () => "group-480"
+    );
+    assert.equal(added.groupId, "group-480");
+    assert.deepEqual(
+      added.balance.groups.map((group) => [group.id, group.sortOrder]),
+      [["group-410", 0], ["group-440", 1], ["group-480", 2]]
+    );
+    assert.equal(added.balance.groups[2]!.editor, null);
+
+    const edited = updateEstimateGroup(added.balance, "group-480", {
+      costGroup: "481",
+      editor: "MSR",
+    });
+    assert.equal(edited.groups[2]!.costGroup, "481");
+    assert.equal(edited.groups[2]!.title, "Gebäudeautomation");
+
+    const movedUp = moveEstimateGroup(edited, "group-480", -1);
+    assert.deepEqual(
+      movedUp.groups.map((group) => [group.id, group.sortOrder]),
+      [["group-410", 0], ["group-480", 1], ["group-440", 2]]
+    );
+    assert.equal(moveEstimateGroup(movedUp, "group-440", 1), movedUp);
+
+    const removed = removeEstimateGroup(movedUp, "group-410");
+    assert.deepEqual(
+      removed.groups.map((group) => [group.id, group.sortOrder]),
+      [["group-480", 0], ["group-440", 1]]
+    );
+    assert.equal(removeEstimateGroup(removed, "missing"), removed);
+  });
+
+  it("orders loaded documents by sortOrder", () => {
+    const balance = sampleBalance();
+    const shuffled: EstimateBalanceSnapshot = {
+      ...balance,
+      groups: [
+        { ...balance.groups[1]!, sortOrder: 7 },
+        {
+          ...balance.groups[0]!,
+          sortOrder: 2,
+          rows: [
+            { ...balance.groups[0]!.rows[1]!, sortOrder: 5 },
+            { ...balance.groups[0]!.rows[0]!, sortOrder: 1 },
+          ],
+        },
+      ],
+    };
+    const normalized = normalizeEstimateSortOrder(shuffled);
+    assert.deepEqual(
+      normalized.groups.map((group) => [group.id, group.sortOrder]),
+      [["group-410", 0], ["group-440", 1]]
+    );
+    assert.deepEqual(
+      normalized.groups[0]!.rows.map((row) => [row.id, row.sortOrder]),
+      [["row-a", 0], ["row-b", 1]]
+    );
+  });
+});
+
+describe("estimate balance saving", () => {
+  it("builds the trimmed server document with null for empty optional texts", () => {
+    let balance = sampleBalance();
+    balance = { ...balance, name: "  Entwurf ", workStage: "  ", dateIso: "" };
+    balance = updateEstimateGroup(balance, "group-440", { title: " Starkstrom ", editor: " " });
+    balance = updateEstimateRow(balance, "group-410", "row-a", {
+      name: " Hebeanlage ",
+      supply: " ELT ",
+      remark: "   ",
+    });
+    const saveable = toSaveableEstimateBalance(balance);
+    assert.equal(saveable.name, "Entwurf");
+    assert.equal(saveable.workStage, null);
+    assert.equal(saveable.dateIso, null);
+    assert.equal(saveable.groups[1]!.title, "Starkstrom");
+    assert.equal(saveable.groups[1]!.editor, null);
+    assert.deepEqual(
+      {
+        name: saveable.groups[0]!.rows[0]!.name,
+        supply: saveable.groups[0]!.rows[0]!.supply,
+        remark: saveable.groups[0]!.rows[0]!.remark,
+      },
+      { name: "Hebeanlage", supply: "ELT", remark: null }
+    );
+  });
+
+  it("copies only snapshot fields", () => {
+    const balance = sampleBalance() as EstimateBalanceSnapshot & { uiState?: string };
+    balance.uiState = "leak";
+    assert.equal("uiState" in toSaveableEstimateBalance(balance), false);
+  });
+
+  it("treats whitespace-only changes as unchanged", () => {
+    const balance = sampleBalance();
+    const withSpace = updateEstimateRow(balance, "group-410", "row-a", {
+      name: "Hebeanlage ",
+    });
+    assert.equal(estimateBalanceFingerprint(withSpace), estimateBalanceFingerprint(balance));
+    const changed = updateEstimateRow(balance, "group-410", "row-a", { quantity: 2 });
+    assert.notEqual(estimateBalanceFingerprint(changed), estimateBalanceFingerprint(balance));
+  });
+
+  it("reports documents the server would reject", () => {
+    assert.deepEqual(validateEstimateBalance(sampleBalance()), []);
+    const invalid = updateEstimateGroup(
+      { ...sampleBalance(), name: "  " },
+      "group-440",
+      { title: " " }
+    );
+    assert.equal(validateEstimateBalance(invalid).length, 2);
+  });
+
+  it("names copies", () => {
+    assert.equal(createCopyName("Entwurfsplanung "), "Entwurfsplanung (Kopie)");
+    assert.equal(createCopyName("x".repeat(200)).length, 200);
+  });
+});
+
+describe("estimate balance frontend API", () => {
+  it("calls the estimate balance endpoints", async () => {
+    const requests: Array<{ url: string; method: string; body: unknown; keepalive?: boolean }> =
+      [];
+    const originalFetch = globalThis.fetch;
+    globalThis.fetch = async (input, init) => {
+      requests.push({
+        url: String(input),
+        method: init?.method ?? "GET",
+        body: init?.body === undefined ? undefined : JSON.parse(String(init.body)),
+        ...(init?.keepalive ? { keepalive: true } : {}),
+      });
+      return new Response(JSON.stringify({}), {
+        status: 200,
+        headers: { "Content-Type": "application/json" },
+      });
+    };
+    try {
+      const balance = sampleBalance();
+      await listEstimateBalances("project-1");
+      await getEstimateBalance("project-1", "balance-1");
+      await createEstimateBalance(
+        "project-1",
+        { name: "Vorplanung", workStage: null, dateIso: "2026-09-26", template: "kg400" },
+        4
+      );
+      await createEstimateBalance(
+        "project-1",
+        { name: "Kopie", template: "copy", copyFromBalanceId: "balance-1" },
+        5
+      );
+      await updateEstimateBalance("project-1", balance, 6);
+      await updateEstimateBalance("project-1", balance, 7, { keepalive: true });
+      await deleteEstimateBalance("project-1", "balance-1", 8);
+      await getEstimateComparison("project-1", "balance-1");
+      const base = "/api/projects/project-1/estimate-balances";
+      assert.deepEqual(requests, [
+        { url: base, method: "GET", body: undefined },
+        { url: `${base}/balance-1`, method: "GET", body: undefined },
+        {
+          url: base,
+          method: "POST",
+          body: {
+            name: "Vorplanung",
+            workStage: null,
+            dateIso: "2026-09-26",
+            template: "kg400",
+            expectedRevision: 4,
+          },
+        },
+        {
+          url: base,
+          method: "POST",
+          body: {
+            name: "Kopie",
+            template: "copy",
+            copyFromBalanceId: "balance-1",
+            expectedRevision: 5,
+          },
+        },
+        {
+          url: `${base}/balance-1`,
+          method: "PUT",
+          body: { expectedRevision: 6, balance },
+        },
+        {
+          url: `${base}/balance-1`,
+          method: "PUT",
+          body: { expectedRevision: 7, balance },
+          keepalive: true,
+        },
+        { url: `${base}/balance-1`, method: "DELETE", body: { expectedRevision: 8 } },
+        { url: `${base}/balance-1/comparison`, method: "GET", body: undefined },
+      ]);
+    } finally {
+      globalThis.fetch = originalFetch;
+    }
+  });
+
+  it("exposes status and code of failed requests", async () => {
+    const originalFetch = globalThis.fetch;
+    globalThis.fetch = async () =>
+      new Response(
+        JSON.stringify({
+          error: "Projektstand veraltet.",
+          code: "PROJECT_REVISION_CONFLICT",
+        }),
+        { status: 409, headers: { "Content-Type": "application/json" } }
+      );
+    try {
+      await assert.rejects(
+        updateEstimateBalance("project-1", sampleBalance(), 1),
+        (error: unknown) => {
+          assert.ok(error instanceof ApiRequestError);
+          assert.equal(error.message, "Projektstand veraltet.");
+          assert.equal(error.status, 409);
+          assert.equal(error.code, "PROJECT_REVISION_CONFLICT");
+          assert.equal(isRevisionConflictError(error), true);
+          return true;
+        }
+      );
+    } finally {
+      globalThis.fetch = originalFetch;
+    }
+    assert.equal(isRevisionConflictError(new ApiRequestError("x", 400)), false);
+    assert.equal(isRevisionConflictError(new Error("x")), false);
+  });
+});

tests/estimate-balance.test.ts

@@ -0,0 +1,458 @@
+import path from "node:path";
+import assert from "node:assert/strict";
+import { describe, it } from "node:test";
+import { migrate } from "drizzle-orm/better-sqlite3/migrator";
+import {
+  createDatabaseContext,
+  type DatabaseContext,
+} from "../src/db/database-context.js";
+import { EstimateBalanceProjectCommandRepository } from "../src/db/repositories/estimate-balance-project-command.repository.js";
+import { EstimateBalanceRepository } from "../src/db/repositories/estimate-balance.repository.js";
+import { ProjectHistoryRepository } from "../src/db/repositories/project-history.repository.js";
+import { circuitDeviceRows } from "../src/db/schema/circuit-device-rows.js";
+import { circuitLists } from "../src/db/schema/circuit-lists.js";
+import { circuitSections } from "../src/db/schema/circuit-sections.js";
+import { circuits } from "../src/db/schema/circuits.js";
+import { distributionBoards } from "../src/db/schema/distribution-boards.js";
+import { estimateRows } from "../src/db/schema/estimate-balances.js";
+import { projects } from "../src/db/schema/projects.js";
+import {
+  createEstimateBalanceDeleteProjectCommand,
+  createEstimateBalanceInsertProjectCommand,
+  createEstimateBalanceSnapshot,
+  createEstimateBalanceUpdateProjectCommand,
+  parseEstimateBalanceSnapshot,
+  type EstimateBalanceProjectCommand,
+} from "../src/estimate-balance/domain/estimate-balance-command.model.js";
+import { createEstimateBalanceRequestSchema } from "../src/estimate-balance/api/estimate-balance-request.schemas.js";
+import {
+  calculateEstimateBalance,
+  calculateEstimateRow,
+  compareEstimateWithDetailed,
+  estimateDefaultGroups,
+  matchEstimateCostGroup,
+  roundEstimateValue,
+  type EstimateBalanceSnapshot,
+  type EstimateRowSnapshot,
+} from "../src/shared/estimate-balance/estimate-balance.js";
+
+const round2 = (value: number) => roundEstimateValue(value, 2);
+let nextId = 0;
+const id = () => `id-${++nextId}`;
+
+function row(
+  name: string,
+  quantity: number,
+  powerPerUnitW: number,
+  simultaneityFactor: number,
+  cosPhi: number,
+  extra: Partial<EstimateRowSnapshot> = {}
+): EstimateRowSnapshot {
+  return {
+    id: id(),
+    sortOrder: 0,
+    supply: "ELT",
+    name,
+    quantity,
+    unit: "piece",
+    connection: null,
+    powerPerUnitW,
+    simultaneityFactor,
+    cosPhi,
+    safetySupply: false,
+    remark: null,
+    ...extra,
+  };
+}
+
+/** All rows of the office example "Leistungsbilanz - KG400" (Entwurfsplanung). */
+function templateExample(): EstimateBalanceSnapshot {
+  const rowsByGroup: Record<string, EstimateRowSnapshot[]> = {
+    "410": [
+      row("Durchlauferhitzer 11kW", 9, 11200, 0.3, 1),
+      row("Durchlauferhitzer 4,4kW", 4, 4400, 0.3, 1),
+    ],
+    "420": [
+      row("Fernwärmestation", 1, 1000, 0.8, 1),
+      row("Pumpen", 4, 200, 0.8, 0.9),
+      row("Schaltschrank Heizung", 1, 2000, 0.8, 1),
+    ],
+    "430": [
+      row("Lüftungsgerät", 1, 6000, 0.8, 0.9),
+      row("Schaltschrank Lüftung", 1, 2000, 0.8, 0.9),
+    ],
+    "434": [
+      row("Kälteaggregat Dach", 1, 1000, 0.8, 1),
+      row("Serverraum Kühlung Aggregat Dach", 1, 2000, 0.8, 1),
+      row("Serverraum Innengerät", 1, 1000, 0.8, 1),
+    ],
+    "440": [
+      row("Beleuchtungsanlage Klassenzimmer", 17, 500, 0.8, 0.95),
+      row("Beleuchtung Allgemein", 50, 45, 0.7, 0.95),
+      row("Außenbeleuchtung", 10, 100, 0.4, 0.95),
+      row("Fassadenbeleuchtung", 20, 60, 0.5, 0.95),
+      row("Beleuchtung MFR", 15, 50, 0.8, 0.95),
+      row("Steckdosen Klassenzimmer", 170, 300, 0.2, 0.95),
+      row("Steckdosen 230 V allg. Verbr.", 100, 500, 0.2, 0.95),
+      row("Veranstaltungstechnik", 1, 4000, 0.5, 0.95),
+      row("Küchentechnische Anlagen", 1, 10000, 0.4, 0.8),
+      row("Sicherheitsbeleuchtung Zentrale", 1, 2000, 0.8, 0.9),
+      row("Spezielle Experimentieranlagen", 1, 6000, 0.4, 0.9),
+    ],
+    "450": [row("EDV Systeme", 5, 3000, 0.8, 0.95)],
+    "460": [row("Aufzug", 1, 16000, 0.7, 0.95)],
+    "470": [row("E-Mobility Vorbereitung", 9, 11000, 0.3, 1)],
+    "480": [],
+    "": [row("Allgemein", 1, 2000, 1, 0.95)],
+  };
+  return {
+    id: "balance-1",
+    projectId: "project-1",
+    name: "Entwurfsplanung",
+    workStage: "LPH 3",
+    dateIso: "2023-06-30",
+    reserveAvPercent: 10,
+    reserveSvPercent: 0,
+    sortOrder: 0,
+    groups: estimateDefaultGroups.map((group, index) => ({
+      id: `group-${group.costGroup || "allg"}`,
+      costGroup: group.costGroup,
+      title: group.title,
+      editor: null,
+      sortOrder: index,
+      rows: rowsByGroup[group.costGroup] ?? [],
+    })),
+  };
+}
+
+function createTestDatabase(): DatabaseContext {
+  const context = createDatabaseContext(":memory:");
+  migrate(context.db, { migrationsFolder: path.resolve("src", "db", "migrations") });
+  context.db
+    .insert(projects)
+    .values([
+      { id: "project-1", name: "Test project" },
+      { id: "project-2", name: "Foreign project" },
+    ])
+    .run();
+  return context;
+}
+
+describe("estimate balance calculation", () => {
+  it("reproduces the office template totals", () => {
+    const result = calculateEstimateBalance(templateExample(), 400);
+    const groupTotals = result.groups.map((group) => [
+      round2(group.av.kw),
+      round2(group.av.kva),
+    ]);
+    assert.deepEqual(groupTotals, [
+      [35.52, 35.52],
+      [3.04, 3.11],
+      [6.4, 7.11],
+      [3.2, 3.2],
+      [40.18, 43.31],
+      [12, 12.63],
+      [11.2, 11.79],
+      [29.7, 29.7],
+      [0, 0],
+      [2, 2.11],
+    ]);
+    assert.equal(round2(result.total.av.kw), 143.24);
+    assert.equal(round2(result.total.av.kva), 148.48);
+    assert.equal(round2(result.reserve.av.kw), 14.32);
+    assert.equal(round2(result.reserve.av.kva), 14.85);
+    assert.equal(round2(result.withReserve.av.kw), 157.56);
+    assert.equal(round2(result.withReserve.av.kva), 163.33);
+    assert.equal(round2(result.maxCurrentA.av), 235.75);
+    assert.equal(result.total.sv.kw, 0);
+    assert.equal(result.maxCurrentA.sv, 0);
+  });
+
+  it("counts safety-supply rows in AV and additionally in SV, also per m²", () => {
+    const area = calculateEstimateRow({
+      quantity: 250,
+      powerPerUnitW: 12,
+      simultaneityFactor: 0.8,
+      cosPhi: 0.95,
+      safetySupply: true,
+    });
+    assert.equal(round2(area.av.kw), 2.4);
+    assert.equal(round2(area.av.kva), 2.53);
+    assert.deepEqual(area.sv, area.av);
+    const balance = templateExample();
+    balance.reserveSvPercent = 20;
+    balance.groups[4]!.rows[9]!.safetySupply = true; // Sicherheitsbeleuchtung Zentrale
+    const result = calculateEstimateBalance(balance, 400);
+    assert.equal(round2(result.total.sv.kw), 1.6);
+    assert.equal(round2(result.withReserve.sv.kw), 1.92);
+    assert.equal(round2(result.total.av.kw), 143.24);
+  });
+
+  it("rounds displayed values like the spreadsheet", () => {
+    assert.equal(roundEstimateValue(40.175), 40.18);
+    assert.equal(roundEstimateValue(143.235), 143.24);
+    assert.equal(roundEstimateValue(-1.825), -1.83);
+    assert.equal(roundEstimateValue(0.711111), 0.71);
+    assert.equal(roundEstimateValue(235.749, 1), 235.7);
+  });
+
+  it("matches detailed cost groups to the most specific estimate group", () => {
+    const codes = ["410", "430", "434", "440", "480", ""];
+    assert.equal(matchEstimateCostGroup("444", codes), "440");
+    assert.equal(matchEstimateCostGroup("434", codes), "434");
+    assert.equal(matchEstimateCostGroup("431", codes), "430");
+    assert.equal(matchEstimateCostGroup("KG 481.1", codes), "480");
+    assert.equal(matchEstimateCostGroup("4", codes), null);
+    assert.equal(matchEstimateCostGroup("", codes), null);
+    assert.equal(matchEstimateCostGroup(null, codes), null);
+    assert.equal(matchEstimateCostGroup("450", codes), null);
+  });
+
+  it("compares the estimate with detailed device rows per cost group", () => {
+    const comparison = compareEstimateWithDetailed(templateExample(), [
+      { costGroup: "444", kw: 30, cosPhi: 0.9 },
+      { costGroup: "445", kw: 12, cosPhi: null },
+      { costGroup: "412", kw: 40, cosPhi: 1 },
+      { costGroup: null, kw: 5, cosPhi: 1 },
+      { costGroup: "399", kw: 1, cosPhi: 1 },
+    ]);
+    const kg440 = comparison.groups.find((group) => group.costGroup === "440")!;
+    assert.equal(round2(kg440.detailed.kw), 42);
+    assert.equal(round2(kg440.detailed.kva), 45.33);
+    assert.equal(kg440.detailedRowCount, 2);
+    assert.ok(Math.abs(kg440.deltaKw - 1.825) < 1e-9);
+    assert.equal(round2(kg440.deltaPercent!), 4.54);
+    const kg410 = comparison.groups.find((group) => group.costGroup === "410")!;
+    assert.equal(round2(kg410.deltaKw), 4.48);
+    const kg480 = comparison.groups.find((group) => group.costGroup === "480")!;
+    assert.equal(kg480.deltaPercent, null);
+    assert.deepEqual(comparison.unassigned, { kw: 6, kva: 6, rowCount: 2 });
+    assert.equal(round2(comparison.total.detailed.kw), 88);
+    assert.equal(round2(comparison.total.estimatedAv.kw), 143.24);
+  });
+});
+
+describe("estimate balance snapshots and commands", () => {
+  it("validates snapshots strictly", () => {
+    const valid = templateExample();
+    assert.equal(parseEstimateBalanceSnapshot(valid).groups[4]!.rows[3]!.sortOrder, 3);
+    const invalid: Array<(balance: EstimateBalanceSnapshot) => void> = [
+      (balance) => (balance.groups[0]!.rows[0]!.cosPhi = 0),
+      (balance) => (balance.groups[0]!.rows[0]!.simultaneityFactor = 1.5),
+      (balance) => (balance.groups[0]!.rows[0]!.quantity = -1),
+      (balance) => (balance.groups[0]!.rows[0]!.name = " Leerzeichen "),
+      (balance) => (balance.groups[0]!.rows[0]!.supply = ""),
+      (balance) => (balance.groups[0]!.title = ""),
+      (balance) => (balance.dateIso = "30.06.2023"),
+      (balance) => (balance.reserveAvPercent = 101),
+      (balance) => (balance.groups[1]!.rows[0]!.id = balance.groups[0]!.rows[0]!.id),
+      (balance) => ((balance.groups[0]!.rows[0] as unknown as Record<string, unknown>).extra = 1),
+    ];
+    for (const mutate of invalid) {
+      const balance = structuredClone(valid);
+      mutate(balance);
+      assert.throws(() => parseEstimateBalanceSnapshot(balance));
+    }
+    assert.equal(
+      createEstimateBalanceRequestSchema.safeParse({
+        expectedRevision: 0,
+        name: "Entwurf",
+        template: "copy",
+      }).success,
+      false
+    );
+  });
+
+  it("creates the KG 400 template and copies a Stand with new ids", () => {
+    const created = createEstimateBalanceSnapshot({
+      projectId: "project-1",
+      name: " Vorplanung ",
+      workStage: "LPH 2",
+      dateIso: "2026-09-26",
+      sortOrder: 0,
+      template: "kg400",
+    });
+    assert.equal(created.name, "Vorplanung");
+    assert.deepEqual(
+      created.groups.map((group) => group.costGroup),
+      estimateDefaultGroups.map((group) => group.costGroup)
+    );
+    assert.equal(created.reserveAvPercent, 10);
+    const source = templateExample();
+    const copy = createEstimateBalanceSnapshot({
+      projectId: "project-1",
+      name: "Entwurfsplanung Kopie",
+      workStage: null,
+      dateIso: null,
+      sortOrder: 1,
+      template: { copyFrom: source },
+    });
+    assert.notEqual(copy.id, source.id);
+    assert.notEqual(copy.groups[0]!.id, source.groups[0]!.id);
+    assert.notEqual(copy.groups[0]!.rows[0]!.id, source.groups[0]!.rows[0]!.id);
+    assert.equal(
+      round2(calculateEstimateBalance(copy, 400).total.av.kw),
+      143.24
+    );
+  });
+
+  it("inserts, updates and deletes balances with persisted undo and redo", () => {
+    const context = createTestDatabase();
+    try {
+      const store = new EstimateBalanceProjectCommandRepository(context.db);
+      const reader = new EstimateBalanceRepository(context.db);
+      const history = new ProjectHistoryRepository(context.db);
+      let revision = 0;
+      const run = (
+        command: EstimateBalanceProjectCommand,
+        source: "user" | "undo" | "redo" = "user"
+      ) => {
+        const step = source === "user" ? null : history.getNextCommand("project-1", source);
+        const result = store.execute({
+          projectId: "project-1",
+          expectedRevision: revision,
+          source,
+          historyTargetChangeSetId: step?.changeSetId,
+          command,
+        });
+        revision += 1;
+        return result;
+      };
+
+      const balance = templateExample();
+      const insert = createEstimateBalanceInsertProjectCommand(balance);
+      const inserted = run(insert);
+      const stored = reader.findById("project-1", balance.id);
+      assert.deepEqual(stored, parseEstimateBalanceSnapshot(balance));
+      assert.equal(reader.listByProject("project-2").length, 0);
+
+      const target = structuredClone(stored!);
+      target.groups[0]!.rows.splice(1, 1);
+      target.groups[0]!.rows[0]!.quantity = 10;
+      target.groups[8]!.rows.push(row("GLT-Schrank", 2, 500, 1, 0.95));
+      target.groups[8]!.editor = "MSR";
+      target.reserveAvPercent = 15;
+      const update = createEstimateBalanceUpdateProjectCommand(stored!, target);
+      const updated = run(update);
+      assert.deepEqual(
+        reader.findById("project-1", balance.id),
+        parseEstimateBalanceSnapshot(target)
+      );
+
+      run(updated.inverse, "undo");
+      assert.deepEqual(reader.findById("project-1", balance.id), stored);
+      run(update, "redo");
+      assert.deepEqual(
+        reader.findById("project-1", balance.id),
+        parseEstimateBalanceSnapshot(target)
+      );
+
+      // A stale expected document is rejected.
+      assert.throws(
+        () => run(createEstimateBalanceUpdateProjectCommand(stored!, { ...stored!, name: "X" })),
+        /changed before update/
+      );
+      assert.throws(
+        () => createEstimateBalanceUpdateProjectCommand(stored!, structuredClone(stored!)),
+        /must change/
+      );
+
+      const current = reader.findById("project-1", balance.id)!;
+      const deleted = run(createEstimateBalanceDeleteProjectCommand(current));
+      assert.equal(reader.findById("project-1", balance.id), null);
+      assert.equal(context.db.select().from(estimateRows).all().length, 0);
+      run(deleted.inverse, "undo");
+      assert.deepEqual(reader.findById("project-1", balance.id), current);
+      // The original insert's inverse no longer matches the edited balance.
+      assert.throws(() => run(inserted.inverse), /changed before deletion/);
+      run(createEstimateBalanceDeleteProjectCommand(current));
+      assert.equal(reader.listByProject("project-1").length, 0);
+
+      assert.throws(
+        () => run(createEstimateBalanceInsertProjectCommand({ ...balance, projectId: "project-2" })),
+        /does not belong to project/
+      );
+    } finally {
+      context.close();
+    }
+  });
+
+  it("sums detailed device rows of all circuit lists of the project", () => {
+    const context = createTestDatabase();
+    try {
+      context.db
+        .insert(distributionBoards)
+        .values({ id: "board-1", projectId: "project-1", name: "UV 1" })
+        .run();
+      context.db
+        .insert(circuitLists)
+        .values({ id: "list-1", projectId: "project-1", distributionBoardId: "board-1", name: "UV 1" })
+        .run();
+      context.db
+        .insert(circuitSections)
+        .values({
+          id: "section-1",
+          circuitListId: "list-1",
+          key: "lighting-1",
+          displayName: "Beleuchtung 1",
+          prefix: "1F1",
+          sortOrder: 0,
+        })
+        .run();
+      context.db
+        .insert(circuits)
+        .values({
+          id: "circuit-1",
+          circuitListId: "list-1",
+          sectionId: "section-1",
+          equipmentIdentifier: "-1F1",
+          displayName: "Licht",
+          sortOrder: 0,
+        })
+        .run();
+      context.db
+        .insert(circuitDeviceRows)
+        .values([
+          {
+            id: "row-1",
+            circuitId: "circuit-1",
+            name: "Leuchte",
+            displayName: "Leuchte",
+            costGroup: "445",
+            quantity: 10,
+            powerPerUnit: 0.05,
+            simultaneityFactor: 0.8,
+            cosPhi: 0.95,
+          },
+          {
+            id: "row-2",
+            circuitId: "circuit-1",
+            name: "Steckdose",
+            displayName: "Steckdose",
+            costGroup: null,
+            quantity: 2,
+            powerPerUnit: 0.2,
+            simultaneityFactor: 0.5,
+            cosPhi: null,
+          },
+        ])
+        .run();
+      const detailed = new EstimateBalanceRepository(context.db).listDetailedDeviceRowPower(
+        "project-1"
+      );
+      assert.deepEqual(
+        detailed.map((entry) => ({ ...entry, kw: round2(entry.kw) })),
+        [
+          { costGroup: "445", kw: 0.4, cosPhi: 0.95 },
+          { costGroup: null, kw: 0.2, cosPhi: null },
+        ]
+      );
+      assert.equal(
+        new EstimateBalanceRepository(context.db).listDetailedDeviceRowPower("project-2").length,
+        0
+      );
+    } finally {
+      context.close();
+    }
+  });
+});

tests/print-view-migration.test.ts

@@ -49,6 +49,9 @@ it("upgrades a populated pre-print database through the current schema without c
     assert.equal(context.sqlite.prepare("SELECT count(*) AS count FROM buildings").get()!.count, 0);
     assert.equal(context.sqlite.prepare("SELECT count(*) AS count FROM document_branding_assets").get()!.count, 0);
     assert.equal(context.sqlite.prepare("SELECT count(*) AS count FROM document_branding_settings").get()!.count, 0);
+    assert.equal(context.sqlite.prepare("SELECT count(*) AS count FROM estimate_balances").get()!.count, 0);
+    assert.equal(context.sqlite.prepare("SELECT count(*) AS count FROM estimate_groups").get()!.count, 0);
+    assert.equal(context.sqlite.prepare("SELECT count(*) AS count FROM estimate_rows").get()!.count, 0);
     assert.deepEqual(context.sqlite.pragma("foreign_key_check"), []);
     assert.equal(context.sqlite.pragma("integrity_check", { simple: true }), "ok");
     migrate(context.db, { migrationsFolder: source });

tests/project-snapshot.repository.test.ts

@@ -11,7 +11,13 @@ import {
 import { DistributionBoardFixtureRepository } from "./support/distribution-board-fixture.js";
 import { ProjectSnapshotRepository } from "../src/db/repositories/project-snapshot.repository.js";
 import { ProjectTransferRepository } from "../src/db/repositories/project-transfer.repository.js";
+import { ProjectStateRestoreCommandRepository } from "../src/db/repositories/project-state-restore-command.repository.js";
 import { readProjectStateSnapshot } from "../src/db/repositories/project-state-snapshot.persistence.js";
+import {
+  deleteEstimateBalance,
+  insertEstimateBalance,
+  readEstimateBalances,
+} from "../src/db/repositories/estimate-balance.persistence.js";
 import { circuitDeviceRows } from "../src/db/schema/circuit-device-rows.js";
 import { circuitLists } from "../src/db/schema/circuit-lists.js";
 import { circuitProtectionDevices } from "../src/db/schema/circuit-protection-devices.js";
@@ -28,8 +34,48 @@ import { projects } from "../src/db/schema/projects.js";
 import { rooms } from "../src/db/schema/rooms.js";
 import { deserializeProjectStateSnapshot } from "../src/domain/models/project-state-snapshot.model.js";
 import { projectStateSnapshotSchemaVersion } from "../src/domain/models/project-state-snapshot.model.js";
+import { createProjectStateRestoreCommand } from "../src/domain/models/project-state-restore-command.model.js";
 import { ProjectRevisionConflictError } from "../src/domain/errors/project-revision-conflict.error.js";
 import { ProjectSnapshotNameConflictError } from "../src/domain/errors/project-snapshot-name-conflict.error.js";
+import { parseEstimateBalanceSnapshot } from "../src/estimate-balance/domain/estimate-balance-command.model.js";
+
+function estimateBalance(projectId: string, suffix = "") {
+  return parseEstimateBalanceSnapshot({
+    id: `estimate${suffix}`,
+    projectId,
+    name: `Vorplanung${suffix}`,
+    workStage: "LPH 2",
+    dateIso: "2026-09-27",
+    reserveAvPercent: 10,
+    reserveSvPercent: 5,
+    sortOrder: 0,
+    groups: [
+      {
+        id: `estimate-group${suffix}`,
+        costGroup: "440",
+        title: "Starkstromanlagen",
+        editor: "Planung",
+        sortOrder: 0,
+        rows: [
+          {
+            id: `estimate-row${suffix}`,
+            sortOrder: 0,
+            supply: "ELT",
+            name: "Beleuchtung",
+            quantity: 100,
+            unit: "area",
+            connection: "fixed",
+            powerPerUnitW: 12,
+            simultaneityFactor: 0.8,
+            cosPhi: 0.95,
+            safetySupply: false,
+            remark: null,
+          },
+        ],
+      },
+    ],
+  });
+}
 
 function createTestDatabase(): DatabaseContext {
   const context = createDatabaseContext(":memory:");
@@ -463,14 +509,41 @@ describe("project snapshot repository", () => {
 });
 
 describe("portable project transfer", () => {
+  it("keeps estimate balances outside normal snapshot restore", () => {
+    const context = createTestDatabase();
+    try {
+      insertEstimateBalance(context.db, estimateBalance("project-1"));
+      const current = readProjectStateSnapshot(context.db, "project-1");
+      assert.ok(current);
+      new ProjectStateRestoreCommandRepository(context.db).execute({
+        projectId: "project-1",
+        expectedRevision: 0,
+        source: "restore",
+        command: createProjectStateRestoreCommand(current.payloadSha256, {
+          ...current.state,
+          project: { ...current.state.project, name: "Restored project" },
+        }),
+      });
+      assert.deepEqual(
+        readEstimateBalances(context.db, "project-1").map((entry) => entry.id),
+        ["estimate"]
+      );
+    } finally {
+      context.close();
+    }
+  });
+
   it("exports and atomically duplicates a complete project with new ids", () => {
     const context = createTestDatabase();
     try {
       context.db.update(projects).set({ siteAddress: "Musterstraße 1", workStage: "LPH 5", projectLead: "Planung", projectEditor: "Test" }).where(eq(projects.id, "project-1")).run();
       context.db.update(distributionBoards).set({ boardNumber: "UV-01", location: "Technik", fedFrom: "HAK", remark: "Prüfstand" }).where(eq(distributionBoards.projectId, "project-1")).run();
+      insertEstimateBalance(context.db, estimateBalance("project-1"));
       const repository = new ProjectTransferRepository(context.db);
       const transfer = repository.exportProject("project-1");
       assert.ok(transfer);
+      assert.equal(transfer.formatVersion, 2);
+      assert.equal(transfer.estimateBalances.length, 1);
       const duplicate = repository.importDuplicate(transfer);
       assert.notEqual(duplicate.projectId, "project-1");
       assert.equal(duplicate.name, "Snapshot-Projekt (Kopie)");
@@ -541,6 +614,18 @@ describe("portable project transfer", () => {
         copied.state.distributionBoards[0].simultaneityFactor,
         0.65
       );
+      const copiedBalances = readEstimateBalances(context.db, duplicate.projectId);
+      assert.equal(copiedBalances.length, 1);
+      assert.notEqual(copiedBalances[0].id, transfer.estimateBalances[0].id);
+      assert.notEqual(
+        copiedBalances[0].groups[0].id,
+        transfer.estimateBalances[0].groups[0].id
+      );
+      assert.notEqual(
+        copiedBalances[0].groups[0].rows[0].id,
+        transfer.estimateBalances[0].groups[0].rows[0].id
+      );
+      assert.equal(copiedBalances[0].groups[0].rows[0].name, "Beleuchtung");
     } finally {
       context.close();
     }
@@ -566,6 +651,14 @@ describe("portable project transfer", () => {
           }),
         /checksum verification failed/
       );
+      assert.throws(
+        () =>
+          repository.importDuplicate({
+            ...transfer,
+            estimateBalances: [estimateBalance("project-1", "-tampered")],
+          }),
+        /checksum verification failed/
+      );
       assert.equal(
         context.db.select().from(projects).all().length,
         1
@@ -575,15 +668,79 @@ describe("portable project transfer", () => {
     }
   });
 
+  it("imports legacy transfer version 1 with no estimate balances", () => {
+    const context = createTestDatabase();
+    try {
+      const snapshot = readProjectStateSnapshot(context.db, "project-1");
+      assert.ok(snapshot);
+      const legacyTransfer = {
+        format: "leistungsbilanz.project",
+        formatVersion: 1,
+        exportedAtIso: "2026-09-27T12:00:00.000Z",
+        payloadSha256: snapshot.payloadSha256,
+        projectState: snapshot.state,
+      };
+      const duplicate = new ProjectTransferRepository(context.db).importDuplicate(
+        legacyTransfer
+      );
+      assert.deepEqual(
+        readEstimateBalances(context.db, duplicate.projectId),
+        []
+      );
+    } finally {
+      context.close();
+    }
+  });
+
+  it("replaces exported estimate balances atomically and restores them on undo", () => {
+    const context = createTestDatabase();
+    try {
+      insertEstimateBalance(context.db, estimateBalance("project-1"));
+      const transferRepository = new ProjectTransferRepository(context.db);
+      const transfer = transferRepository.exportProject("project-1");
+      assert.ok(transfer);
+
+      deleteEstimateBalance(context.db, "project-1", "estimate");
+      insertEstimateBalance(context.db, estimateBalance("project-1", "-changed"));
+      const prepared = transferRepository.prepareReplace("project-1", transfer);
+      assert.ok(prepared);
+      const restored = new ProjectStateRestoreCommandRepository(context.db).execute({
+        projectId: "project-1",
+        expectedRevision: 0,
+        source: "restore",
+        command: prepared.command,
+      });
+      assert.deepEqual(
+        readEstimateBalances(context.db, "project-1").map((entry) => entry.id),
+        ["estimate"]
+      );
+
+      new ProjectStateRestoreCommandRepository(context.db).execute({
+        projectId: "project-1",
+        expectedRevision: 1,
+        source: "undo",
+        historyTargetChangeSetId: restored.revision.changeSetId,
+        command: restored.inverse,
+      });
+      assert.deepEqual(
+        readEstimateBalances(context.db, "project-1").map((entry) => entry.id),
+        ["estimate-changed"]
+      );
+    } finally {
+      context.close();
+    }
+  });
+
   it("rolls back a duplicate when a late project-state insert fails", () => {
     const context = createTestDatabase();
     try {
+      insertEstimateBalance(context.db, estimateBalance("project-1"));
       const repository = new ProjectTransferRepository(context.db);
       const transfer = repository.exportProject("project-1");
       assert.ok(transfer);
       context.sqlite.exec(`
-        CREATE TRIGGER fail_imported_device_row
-        BEFORE INSERT ON circuit_device_rows
+        CREATE TRIGGER fail_imported_estimate_row
+        BEFORE INSERT ON estimate_rows
         BEGIN
           SELECT RAISE(ABORT, 'forced project transfer failure');
         END;