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/db/repositories/document-branding.repository.ts

@@ -1,9 +1,10 @@
-import { eq } from "drizzle-orm";
+import { eq, inArray } from "drizzle-orm";
 import type { AppDatabase } from "../database-context.js";
 import {
   documentBrandingAssets,
   type DocumentBrandingAsset,
 } from "../schema/document-branding-assets.js";
+import { documentBrandingSettings } from "../schema/document-branding-settings.js";
 
 // Plain repository without revision semantics: branding is global office
 // configuration, not a project mutation.
@@ -49,4 +50,37 @@ export class DocumentBrandingRepository {
         .run().changes > 0
     );
   }
+
+  getSettings<TKey extends string>(keys: readonly TKey[]): Record<TKey, string | null> {
+    const rows = this.db
+      .select()
+      .from(documentBrandingSettings)
+      .where(inArray(documentBrandingSettings.key, [...keys]))
+      .all();
+    return Object.fromEntries(
+      keys.map((key) => [key, rows.find((row) => row.key === key)?.value ?? null])
+    ) as Record<TKey, string | null>;
+  }
+
+  /** Stores the given values atomically; `null` removes a setting. */
+  setSettings(values: Record<string, string | null>) {
+    const updatedAt = new Date();
+    this.db.transaction((tx) => {
+      for (const [key, value] of Object.entries(values)) {
+        if (value === null) {
+          tx.delete(documentBrandingSettings)
+            .where(eq(documentBrandingSettings.key, key))
+            .run();
+        } else {
+          tx.insert(documentBrandingSettings)
+            .values({ key, value, updatedAt })
+            .onConflictDoUpdate({
+              target: documentBrandingSettings.key,
+              set: { value, updatedAt },
+            })
+            .run();
+        }
+      }
+    });
+  }
 }