nearby stations in search

[frephs]

This pull request introduces a "Nearby Stations" feature, allowing users to see train stations closest to their current location. It includes new location permissions, a on-device station database with server sync and caching, UI integration in the station picker dialog, and all supporting utilities.

Nearby stations feature and infrastructure:

• Added NearbyStationsService for fetching, caching, and syncing station data with the server, including fallback to bundled JSON and on-device distance calculation using the Haversine formula (lib/utils/nearby_stations_service.dart, lib/utils/endpoint.dart, lib/utils/shared_preference.dart) [1] [2] [3] [4].
• Implemented LocationService for requesting and checking location permissions and retrieving the user's position (lib/utils/location_service.dart).
• Added location permissions to AndroidManifest.xml and updated dependencies to include geolocator (android/app/src/main/AndroidManifest.xml, pubspec.yaml) [1] [2].

State management and UI integration:

• Introduced NearbyStationsCubit and related states for managing nearby stations loading and error handling (lib/cubit/nearby_stations.dart).
• Integrated the nearby stations list into the station picker dialog UI, including a new NearbyStationsList widget and logic to display it when the search field is empty (lib/view/components/dialog/station_picker.dart, lib/view/components/stations/nearby_stations_list.dart) [1] [2] [3] [4].

Other changes and improvements:

• Improved the saved stations list UI with an icon for clarity (lib/view/components/stations/saved_stations_list.dart).
• Removed a debug print statement from the Strike model (lib/model/Strike.dart).
• Ensured proper initialization of the new service at app startup (lib/main.dart) [1] [2].

These changes together provide users with a seamless way to quickly select nearby stations, with robust handling for offline use and location permissions.