feat(D): Phase D — Undo/Restore komplett implementiert

- D-GEN: RestoreRegistry mit RestoreConfig (model_class, restore_permission, excluded_fields, special_handler)
- D-HOOK: history_hooks.py mit register_history_hooks() für after_create/update/delete
- D-CORE: Company create+update record_history in companies.py
- D-PLUG: Task/Calendar/DMS record_history in services/routes
- D-SOFT: Alle registrierten Entitäten haben deleted_at + un-delete via Registry
- D-MAIL: Mail special_handler (IMAP Trash-Move, Folder-Verify) + record_history in delete/move
- D-TRASH: GET /entity-history/trash (filterbar, paginiert) + Frontend Trash.tsx
- D-TOAST: UndoToast.tsx (5s Auto-Dismiss, useUndoToast Hook)
- D-HIST-UI: HistoryPanel.tsx (Timeline, Diff-View, Restore-Button)
- D-BULK: POST /entity-history/bulk-restore mit partial_success Semantik
- D-RET: POST /entity-history/retention/archive (GDPR hard-delete >90 Tage)
- D-TEST: 26 Tests in test_restore_registry.py, alle grün
- D-DOC: test-strategy.md + security_kernel.md aktualisiert

Backend: 10 Dateien, Frontend: 7 Dateien, Tests: 1 Datei, Docs: 3 Dateien
26/26 Tests passed, TSC 0 errors, App import 492 routes

app/main.py

@@ -333,6 +333,16 @@ async def lifespan(app: FastAPI):
     register_trigger_dispatcher(event_bus)
     logger.info("Trigger dispatcher registered")
 
+    # Register entity restore configurations (Phase D — Undo/Restore)
+    from app.core.restore_registry import register_default_entities
+    register_default_entities()
+    logger.info("Entity restore registry initialized")
+
+    # Register hook-based history recording (Phase D — Undo/Restore)
+    from app.core.history_hooks import register_default_history_hooks
+    register_default_history_hooks()
+    logger.info("History hooks registered")
+
     # Register field definitions from active plugins only
     from app.core.permission_registry import get_permission_registry
     for name in active_plugin_names: