feat: Enhance trip management features and improve UI responsiveness

- Implemented AutomaticKeepAliveClientMixin in HomeContent to maintain state during navigation.
- Modified trip loading logic to trigger after the first frame for better performance.
- Updated trip loading events to use LoadTripsByUserId for consistency.
- Added temporary success messages for trip creation and operations.
- Improved UI elements for better user experience, including updated text styles and spacing.
- Refactored trip model to support Firestore timestamps and improved error handling during parsing.
- Streamlined trip repository methods for better clarity and performance.
- Enhanced trip service methods to ensure correct mapping from Firestore documents.
- Removed unnecessary trip reset logic on logout.

lib/blocs/trip/trip_event.dart

@@ -8,10 +8,10 @@ abstract class TripEvent extends Equatable {
   List<Object?> get props => [];
 }
 
-class TripLoadRequested extends TripEvent {
+class LoadTripsByUserId extends TripEvent {
   final String userId;
 
-  const TripLoadRequested({required this.userId});
+  const LoadTripsByUserId({required this.userId});
 
   @override
   List<Object?> get props => [userId];
@@ -42,38 +42,4 @@ class TripDeleteRequested extends TripEvent {
 
   @override
   List<Object?> get props => [tripId];
-}
-
-class TripParticipantAddRequested extends TripEvent {
-  final String tripId;
-  final String participantEmail;
-
-  const TripParticipantAddRequested({
-    required this.tripId,
-    required this.participantEmail,
-  });
-
-  @override
-  List<Object?> get props => [tripId, participantEmail];
-}
-
-class TripParticipantRemoveRequested extends TripEvent {
-  final String tripId;
-  final String participantEmail;
-
-  const TripParticipantRemoveRequested({
-    required this.tripId,
-    required this.participantEmail,
-  });
-
-  @override
-  List<Object?> get props => [tripId, participantEmail];
-}
-
-// NOUVEAU : Événement pour réinitialiser les trips
-class ResetTrips extends TripEvent {
-  const ResetTrips();
-
-  @override
-  List<Object?> get props => [];
 }