refactor: improve code formatting and organization across multiple files

backend/app/services/network.py

@@ -6,13 +6,14 @@ from typing import Iterable, cast
 
 from geoalchemy2.elements import WKBElement, WKTElement
 from geoalchemy2.shape import to_shape
+
 try:  # pragma: no cover - optional dependency guard
     from shapely.geometry import Point  # type: ignore
 except ImportError:  # pragma: no cover - allow running without shapely at import time
     Point = None  # type: ignore[assignment]
 
-from sqlalchemy.orm import Session
 from sqlalchemy.exc import SQLAlchemyError
+from sqlalchemy.orm import Session
 
 from backend.app.models import StationModel, TrackModel, TrainModel
 from backend.app.repositories import StationRepository, TrackRepository, TrainRepository