Refactor user and theme management to use BLoC pattern; remove provider classes and integrate new services for user and group functionalities

lib/blocs/trip/trip_bloc.dart

@@ -13,6 +13,7 @@ class TripBloc extends Bloc<TripEvent, TripState> {
       : _tripRepository = tripRepository,
         super(TripInitial()) {
     on<TripLoadRequested>(_onLoadRequested);
+    on<_TripUpdated>(_onTripUpdated);
     on<TripCreateRequested>(_onCreateRequested);
     on<TripUpdateRequested>(_onUpdateRequested);
     on<TripDeleteRequested>(_onDeleteRequested);
@@ -29,11 +30,18 @@ class TripBloc extends Bloc<TripEvent, TripState> {
     await _tripsSubscription?.cancel();
     
     _tripsSubscription = _tripRepository.getUserTrips(event.userId).listen(
-      (trips) => add(const _TripUpdated(trips: [])), // Sera géré par un événement interne
+      (trips) => add(_TripUpdated(trips: trips)),
       onError: (error) => emit(TripError(message: error.toString())),
     );
   }
 
+  Future<void> _onTripUpdated(
+    _TripUpdated event,
+    Emitter<TripState> emit,
+  ) async {
+    emit(TripLoaded(trips: event.trips));
+  }
+
   Future<void> _onCreateRequested(
     TripCreateRequested event,
     Emitter<TripState> emit,