feat: Implement trip invitation functionality and notification handling

- Added TripInvitationRepository for managing trip invitations.
- Created TripInvitation model with serialization methods.
- Implemented notification payload parser for handling FCM notifications.
- Enhanced NotificationService to manage trip invitations and related actions.
- Updated UserRepository to include user search functionality.
- Modified AuthRepository to store multiple FCM tokens.
- Added tests for trip invitation logic and notification payload parsing.
- Updated pubspec.yaml and pubspec.lock for dependency management.

lib/pages/home.dart

@@ -16,6 +16,7 @@ import '../services/notification_service.dart';
 import '../services/map_navigation_service.dart';
 import '../services/whats_new_service.dart';
 import '../components/whats_new_dialog.dart';
+import 'trip_invitations_page.dart';
 
 class HomePage extends StatefulWidget {
   const HomePage({super.key});
@@ -227,6 +228,19 @@ class _HomePageState extends State<HomePage> {
               title: "Comptes",
               index: 4,
             ),
+            ListTile(
+              leading: const Icon(Icons.mail_outline),
+              title: const Text('Invitations'),
+              onTap: () {
+                Navigator.pop(context);
+                Navigator.push(
+                  context,
+                  MaterialPageRoute(
+                    builder: (context) => TripInvitationsPage(),
+                  ),
+                );
+              },
+            ),
             const Divider(),
             ListTile(
               leading: const Icon(Icons.logout, color: Colors.red),