Add print cover fields and office profile

- Project settings gain siteAddress, workStage, projectLead and
  projectEditor (project.update-settings schema version 3, migration 0009);
  versions 2 and 1 stay executable and keep the current cover values.
  Snapshot schema 6 carries the fields; older versions upgrade with null.
- Global office profile (office name/address) next to the document logo:
  table document_branding_settings, PUT /api/document-branding/office,
  editable from the print view toolbar.
- Cover page reads all fields; empty values show the "[ergänzen]" marker.
  The Planstände editor column shows the project editor.
- Shared logo constants moved to a dependency-free module so the Next.js
  bundler can import them.

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

src/frontend/components/project-settings-modal.tsx

@@ -7,9 +7,16 @@ import {
   distributionBoardSupplyTypes,
   type DistributionBoardSupplyType,
 } from "../../shared/constants/distribution-board";
+import {
+  projectCoverFieldLabels,
+  projectCoverFieldMaxLengths,
+  projectCoverFields,
+  type ProjectCoverField,
+} from "../../shared/constants/project-cover";
 import { FormModal } from "./form-modal";
 
-export interface ProjectSettingsInput {
+export interface ProjectSettingsInput
+  extends Record<ProjectCoverField, string | null> {
   name: string;
   internalProjectNumber: string | null;
   externalProjectNumber: string | null;
@@ -21,6 +28,13 @@ export interface ProjectSettingsInput {
   enabledDistributionBoardSupplyTypes: DistributionBoardSupplyType[];
 }
 
+const coverFieldPlaceholders: Record<ProjectCoverField, string> = {
+  siteAddress: "Straße Nr.\nPLZ Ort",
+  workStage: "z. B. LPH 5 – Ausführungsplanung",
+  projectLead: "",
+  projectEditor: "",
+};
+
 interface ProjectSettingsModalProps {
   isSaving: boolean;
   onClose: () => void;
@@ -71,6 +85,14 @@ export function ProjectSettingsModal({
   ] = useState<DistributionBoardSupplyType[]>(
     project.enabledDistributionBoardSupplyTypes
   );
+  const [coverValues, setCoverValues] = useState<
+    Record<ProjectCoverField, string>
+  >({
+    siteAddress: project.siteAddress ?? "",
+    workStage: project.workStage ?? "",
+    projectLead: project.projectLead ?? "",
+    projectEditor: project.projectEditor ?? "",
+  });
   const [transfer, setTransfer] = useState<unknown>(null);
   const [transferFilename, setTransferFilename] = useState("");
   const [importMode, setImportMode] = useState<"replace" | "duplicate">(
@@ -91,6 +113,10 @@ export function ProjectSettingsModal({
       singlePhaseVoltageV: Number(singlePhaseVoltageV),
       threePhaseVoltageV: Number(threePhaseVoltageV),
       enabledDistributionBoardSupplyTypes,
+      siteAddress: toNullableString(coverValues.siteAddress),
+      workStage: toNullableString(coverValues.workStage),
+      projectLead: toNullableString(coverValues.projectLead),
+      projectEditor: toNullableString(coverValues.projectEditor),
     });
   }
 
@@ -309,6 +335,57 @@ export function ProjectSettingsModal({
             value={threePhaseVoltageV}
           />
         </div>
+        <div className="col-12">
+          <hr className="my-2" />
+          <h3 className="h6">Deckblatt</h3>
+          <p className="text-secondary small">
+            Angaben für das Deckblatt der Seitenansicht. Büroname und
+            Büroanschrift werden projektübergreifend in der Seitenansicht
+            gepflegt.
+          </p>
+          <div className="row g-3">
+            {projectCoverFields.map((field) => (
+              <div
+                className={field === "siteAddress" ? "col-12" : "col-12 col-md-6"}
+                key={field}
+              >
+                <label className="form-label" htmlFor={`project-cover-${field}`}>
+                  {projectCoverFieldLabels[field]}
+                </label>
+                {field === "siteAddress" ? (
+                  <textarea
+                    className="form-control"
+                    id={`project-cover-${field}`}
+                    maxLength={projectCoverFieldMaxLengths[field]}
+                    onChange={(event) =>
+                      setCoverValues((current) => ({
+                        ...current,
+                        [field]: event.target.value,
+                      }))
+                    }
+                    placeholder={coverFieldPlaceholders[field]}
+                    rows={2}
+                    value={coverValues[field]}
+                  />
+                ) : (
+                  <input
+                    className="form-control"
+                    id={`project-cover-${field}`}
+                    maxLength={projectCoverFieldMaxLengths[field]}
+                    onChange={(event) =>
+                      setCoverValues((current) => ({
+                        ...current,
+                        [field]: event.target.value,
+                      }))
+                    }
+                    placeholder={coverFieldPlaceholders[field]}
+                    value={coverValues[field]}
+                  />
+                )}
+              </div>
+            ))}
+          </div>
+        </div>
         <div className="col-12">
           <hr className="my-2" />
           <h3 className="h6">Projekt importieren oder exportieren</h3>