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.

test/blocs/auth_bloc_test.dart

@@ -8,16 +8,22 @@ import 'package:travel_mate/blocs/auth/auth_state.dart';
 import 'package:travel_mate/repositories/auth_repository.dart';
 import 'package:travel_mate/models/user.dart';
 import 'package:firebase_auth/firebase_auth.dart' as firebase_auth;
+import 'package:firebase_core/firebase_core.dart';
+import 'package:firebase_core_platform_interface/test.dart';
 
 import 'package:travel_mate/services/notification_service.dart';
+import 'package:travel_mate/services/analytics_service.dart';
 
 import 'auth_bloc_test.mocks.dart';
 
 @GenerateMocks([AuthRepository, NotificationService])
 void main() {
+  TestWidgetsFlutterBinding.ensureInitialized();
+
   group('AuthBloc', () {
     late MockAuthRepository mockAuthRepository;
     late MockNotificationService mockNotificationService;
+    late FakeAnalyticsService fakeAnalyticsService;
     late AuthBloc authBloc;
 
     final user = User(
@@ -28,12 +34,19 @@ void main() {
       platform: 'email',
     );
 
+    setUpAll(() async {
+      setupFirebaseCoreMocks();
+      await Firebase.initializeApp();
+    });
+
     setUp(() {
       mockAuthRepository = MockAuthRepository();
       mockNotificationService = MockNotificationService();
+      fakeAnalyticsService = FakeAnalyticsService();
       authBloc = AuthBloc(
         authRepository: mockAuthRepository,
         notificationService: mockNotificationService,
+        analyticsService: fakeAnalyticsService,
       );
 
       // Default stub for saveTokenToFirestore to avoid strict mock errors
@@ -128,3 +141,14 @@ class MockFirebaseUser extends Mock implements firebase_auth.User {
 
   MockFirebaseUser({required this.uid, this.email});
 }
+
+class FakeAnalyticsService extends AnalyticsService {
+  @override
+  Future<void> logEvent({
+    required String name,
+    Map<String, Object>? parameters,
+  }) async {}
+
+  @override
+  Future<void> setUserId(String? id) async {}
+}