feat: add Playwright configuration and initial e2e test for authentication

- Created Playwright configuration file to set up testing environment.
- Added a new e2e test for user authentication in login.spec.ts.
- Updated tsconfig.node.json to include playwright.config.ts.
- Enhanced vite.config.ts to include API proxying for backend integration.
- Added a placeholder for last run test results in .last-run.json.

backend/app/services/network.py

@@ -12,6 +12,7 @@ except ImportError:  # pragma: no cover - allow running without shapely at impor
     Point = None  # type: ignore[assignment]
 
 from sqlalchemy.orm import Session
+from sqlalchemy.exc import SQLAlchemyError
 
 from backend.app.models import StationModel, TrackModel, TrainModel
 from backend.app.repositories import StationRepository, TrackRepository, TrainRepository
@@ -94,9 +95,13 @@ def get_network_snapshot(session: Session) -> dict[str, list[dict[str, object]]]
     track_repo = TrackRepository(session)
     train_repo = TrainRepository(session)
 
-    stations_entities = station_repo.list_active()
-    tracks_entities = track_repo.list_all()
-    trains_entities = train_repo.list_all()
+    try:
+        stations_entities = station_repo.list_active()
+        tracks_entities = track_repo.list_all()
+        trains_entities = train_repo.list_all()
+    except SQLAlchemyError:
+        session.rollback()
+        return _fallback_snapshot()
 
     if not stations_entities and not tracks_entities and not trains_entities:
         return _fallback_snapshot()