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>

docs/circuit-list-editor-known-limitations.md

@@ -31,7 +31,8 @@
   supply structure and "Σ inkl. unterlagert" only from exact text matches with
   board numbers/names and adds values without an upstream simultaneity factor
   (see `docs/print-view.md`).
-- The print view cover page shows placeholders for address, Leistungsphase and
-  office staff, and uses a provisional kbp corporate design. On screen, long
+- The print view uses a kbp corporate design derived from logo and
+  presentation material. Snapshots do not record an editor, so the cover's
+  Planstände list shows the project's current editor for every entry. On screen, long
   board plans are not split into pages; pagination happens in the browser print
   dialog.