Add buildings above floors and a building structure page

Projects with several buildings could not be structured: floors and rooms
hung directly off the project. Floors can now belong to a building
(migration 0009: table buildings, nullable floors.building_id). Rooms and
distribution boards keep their floor; their building follows from it.
Existing floors stay without a building.

Buildings use the location-structure command store with
project-building.insert/.update/.delete, inverses and persistent Undo/Redo;
deleting a building with assigned floors is rejected. Floor commands carry
buildingId since command version 2. Version 1 floor commands from existing
history predate buildings and are upgraded with buildingId = null before
they are executed and persisted, so forward and inverse keep one version.

Project snapshot schema 7 stores buildings and floor.buildingId; versions
1-6 are upgraded without buildings. Restore and portable transfer include
buildings, and the transfer remaps building ids.

Buildings, floors and rooms move from the project overview to their own
page /projects/:id/struktur with three columns (Gebäude -> Etagen -> Räume)
that filter each other, and a sidebar entry. Floor selects in the board and
room dialogs are grouped by building. Unchanged dialogs close without a
command. Details in docs/building-structure.md; see issue #6.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/server/controllers/building.controller.ts

@@ -0,0 +1,111 @@
+import type { Request, Response } from "express";
+import {
+  createProjectBuildingDeleteProjectCommand,
+  createProjectBuildingInsertProjectCommand,
+  createProjectBuildingSnapshot,
+  createProjectBuildingUpdateProjectCommand,
+} from "../../domain/models/project-location-structure-project-command.model.js";
+import {
+  createBuildingSchema,
+  deleteProjectLocationSchema,
+  updateBuildingSchema,
+} from "../../shared/validation/project-structure.schemas.js";
+import { projectCommandService } from "../composition/project-command-stores.js";
+import { buildingRepository } from "../composition/application-repositories.js";
+import { respondWithProjectCommandError } from "./project-command.controller.js";
+
+export async function listBuildingsByProject(req: Request, res: Response) {
+  const { projectId } = req.params;
+  if (typeof projectId !== "string") {
+    return res.status(400).json({ error: "Invalid projectId" });
+  }
+
+  const result = await buildingRepository.listByProject(projectId);
+  return res.json(result);
+}
+
+export async function createBuilding(req: Request, res: Response) {
+  const { projectId } = req.params;
+  if (typeof projectId !== "string") {
+    return res.status(400).json({ error: "Invalid projectId" });
+  }
+
+  const parsed = createBuildingSchema.safeParse(req.body);
+  if (!parsed.success) {
+    return res.status(400).json({ error: parsed.error.flatten() });
+  }
+
+  const existingBuildings = await buildingRepository.listByProject(projectId);
+  const nextSortOrder = existingBuildings.length
+    ? Math.max(...existingBuildings.map((building) => building.sortOrder)) + 1
+    : 0;
+  const building = createProjectBuildingSnapshot(
+    projectId,
+    parsed.data.name,
+    nextSortOrder
+  );
+  try {
+    const result = projectCommandService.executeUser({
+      projectId,
+      expectedRevision: parsed.data.expectedRevision,
+      description: "Gebäude anlegen",
+      command: createProjectBuildingInsertProjectCommand(building),
+    });
+    return res.status(201).json({ ...result, building });
+  } catch (error) {
+    return respondWithProjectCommandError(error, res);
+  }
+}
+
+export async function updateBuilding(req: Request, res: Response) {
+  const { projectId, buildingId } = req.params;
+  if (typeof projectId !== "string" || typeof buildingId !== "string") {
+    return res.status(400).json({ error: "Invalid parameters" });
+  }
+  const parsed = updateBuildingSchema.safeParse(req.body);
+  if (!parsed.success) {
+    return res.status(400).json({ error: parsed.error.flatten() });
+  }
+  const current = await buildingRepository.findById(projectId, buildingId);
+  if (!current) {
+    return res.status(404).json({ error: "Building not found" });
+  }
+  const target = { ...current, name: parsed.data.name };
+  try {
+    const result = projectCommandService.executeUser({
+      projectId,
+      expectedRevision: parsed.data.expectedRevision,
+      description: "Gebäude bearbeiten",
+      command: createProjectBuildingUpdateProjectCommand(current, target),
+    });
+    return res.json({ ...result, building: target });
+  } catch (error) {
+    return respondWithProjectCommandError(error, res);
+  }
+}
+
+export async function deleteBuilding(req: Request, res: Response) {
+  const { projectId, buildingId } = req.params;
+  if (typeof projectId !== "string" || typeof buildingId !== "string") {
+    return res.status(400).json({ error: "Invalid parameters" });
+  }
+  const parsed = deleteProjectLocationSchema.safeParse(req.body);
+  if (!parsed.success) {
+    return res.status(400).json({ error: parsed.error.flatten() });
+  }
+  const current = await buildingRepository.findById(projectId, buildingId);
+  if (!current) {
+    return res.status(404).json({ error: "Building not found" });
+  }
+  try {
+    const result = projectCommandService.executeUser({
+      projectId,
+      expectedRevision: parsed.data.expectedRevision,
+      description: "Gebäude löschen",
+      command: createProjectBuildingDeleteProjectCommand(current),
+    });
+    return res.json(result);
+  } catch (error) {
+    return respondWithProjectCommandError(error, res);
+  }
+}

src/server/controllers/floor.controller.ts

@@ -42,7 +42,8 @@ export async function createFloor(req: Request, res: Response) {
   const floor = createProjectFloorSnapshot(
     projectId,
     parsed.data.name,
-    nextSortOrder
+    nextSortOrder,
+    parsed.data.buildingId ?? null
   );
   try {
     const result = projectCommandService.executeUser({
@@ -70,7 +71,14 @@ export async function updateFloor(req: Request, res: Response) {
   if (!current) {
     return res.status(404).json({ error: "Floor not found" });
   }
-  const target = { ...current, name: parsed.data.name };
+  const target = {
+    ...current,
+    name: parsed.data.name,
+    buildingId:
+      parsed.data.buildingId === undefined
+        ? current.buildingId
+        : parsed.data.buildingId,
+  };
   try {
     const result = projectCommandService.executeUser({
       projectId,