Refactor signup page to use BLoC pattern and implement authentication repository

- Updated signup.dart to replace Provider with BLoC for state management.
- Created AuthRepository to handle authentication logic and Firestore user management.
- Added TripRepository and UserRepository for trip and user data management.
- Implemented methods for user sign-in, sign-up, and data retrieval in repositories.
- Enhanced trip management with create, update, delete, and participant management functionalities.
- Updated AuthService to include new methods for sign-in and sign-up.
- Removed unnecessary print statements from TripService for cleaner code.
- Added dependencies for flutter_bloc and equatable in pubspec.yaml.

Not tested yet

lib/blocs/trip/trip_bloc.dart

@@ -0,0 +1,118 @@
+import 'dart:async';
+import 'package:flutter_bloc/flutter_bloc.dart';
+import '../../repositories/trip_repository.dart';
+import 'trip_event.dart';
+import 'trip_state.dart';
+import '../../data/models/trip.dart';
+
+class TripBloc extends Bloc<TripEvent, TripState> {
+  final TripRepository _tripRepository;
+  StreamSubscription? _tripsSubscription;
+
+  TripBloc({required TripRepository tripRepository})
+      : _tripRepository = tripRepository,
+        super(TripInitial()) {
+    on<TripLoadRequested>(_onLoadRequested);
+    on<TripCreateRequested>(_onCreateRequested);
+    on<TripUpdateRequested>(_onUpdateRequested);
+    on<TripDeleteRequested>(_onDeleteRequested);
+    on<TripParticipantAddRequested>(_onParticipantAddRequested);
+    on<TripParticipantRemoveRequested>(_onParticipantRemoveRequested);
+  }
+
+  Future<void> _onLoadRequested(
+    TripLoadRequested event,
+    Emitter<TripState> emit,
+  ) async {
+    emit(TripLoading());
+
+    await _tripsSubscription?.cancel();
+    
+    _tripsSubscription = _tripRepository.getUserTrips(event.userId).listen(
+      (trips) => add(const _TripUpdated(trips: [])), // Sera géré par un événement interne
+      onError: (error) => emit(TripError(message: error.toString())),
+    );
+  }
+
+  Future<void> _onCreateRequested(
+    TripCreateRequested event,
+    Emitter<TripState> emit,
+  ) async {
+    try {
+      await _tripRepository.createTrip(event.trip);
+      emit(const TripOperationSuccess(message: 'Voyage créé avec succès'));
+    } catch (e) {
+      emit(TripError(message: e.toString()));
+    }
+  }
+
+  Future<void> _onUpdateRequested(
+    TripUpdateRequested event,
+    Emitter<TripState> emit,
+  ) async {
+    try {
+      await _tripRepository.updateTrip(event.trip);
+      emit(const TripOperationSuccess(message: 'Voyage mis à jour'));
+    } catch (e) {
+      emit(TripError(message: e.toString()));
+    }
+  }
+
+  Future<void> _onDeleteRequested(
+    TripDeleteRequested event,
+    Emitter<TripState> emit,
+  ) async {
+    try {
+      await _tripRepository.deleteTrip(event.tripId);
+      emit(const TripOperationSuccess(message: 'Voyage supprimé'));
+    } catch (e) {
+      emit(TripError(message: e.toString()));
+    }
+  }
+
+  Future<void> _onParticipantAddRequested(
+    TripParticipantAddRequested event,
+    Emitter<TripState> emit,
+  ) async {
+    try {
+      await _tripRepository.addParticipant(
+        event.tripId,
+        event.participantEmail,
+      );
+      emit(const TripOperationSuccess(message: 'Participant ajouté'));
+    } catch (e) {
+      emit(TripError(message: e.toString()));
+    }
+  }
+
+  Future<void> _onParticipantRemoveRequested(
+    TripParticipantRemoveRequested event,
+    Emitter<TripState> emit,
+  ) async {
+    try {
+      await _tripRepository.removeParticipant(
+        event.tripId,
+        event.participantEmail,
+      );
+      emit(const TripOperationSuccess(message: 'Participant retiré'));
+    } catch (e) {
+      emit(TripError(message: e.toString()));
+    }
+  }
+
+  @override
+  Future<void> close() {
+    _tripsSubscription?.cancel();
+    return super.close();
+  }
+}
+
+// Événement interne pour les mises à jour du stream
+class _TripUpdated extends TripEvent {
+  final List<Trip> trips;
+
+  const _TripUpdated({required this.trips});
+
+  @override
+  List<Object?> get props => [trips];
+}