feat: Implement activity management feature with Firestore integration

- Added AddActivityBottomSheet for adding custom activities to trips.
- Created Activity model to represent tourist activities.
- Developed ActivityRepository for managing activities in Firestore.
- Integrated ActivityPlacesService for searching activities via Google Places API.
- Updated ShowTripDetailsContent to navigate to activities page.
- Enhanced main.dart to include ActivityBloc and necessary repositories.

lib/main.dart

@@ -4,9 +4,11 @@ import 'package:firebase_core/firebase_core.dart';
 import 'package:travel_mate/blocs/balance/balance_bloc.dart';
 import 'package:travel_mate/blocs/expense/expense_bloc.dart';
 import 'package:travel_mate/blocs/message/message_bloc.dart';
+import 'package:travel_mate/blocs/activity/activity_bloc.dart';
 import 'package:travel_mate/firebase_options.dart';
 import 'package:travel_mate/services/balance_service.dart';
 import 'package:travel_mate/services/error_service.dart';
+import 'package:travel_mate/services/activity_places_service.dart';
 import 'package:flutter_dotenv/flutter_dotenv.dart';
 import 'package:travel_mate/services/expense_service.dart';
 import 'blocs/auth/auth_bloc.dart';
@@ -26,6 +28,7 @@ import 'repositories/message_repository.dart';
 import 'repositories/account_repository.dart';
 import 'repositories/expense_repository.dart';
 import 'repositories/balance_repository.dart';
+import 'repositories/activity_repository.dart';
 import 'pages/login.dart';
 import 'pages/home.dart';
 import 'pages/signup.dart';
@@ -99,6 +102,14 @@ class MyApp extends StatelessWidget {
             expenseRepository: context.read<ExpenseRepository>(),
           ),
         ),
+        // Activity repository for managing trip activities
+        RepositoryProvider<ActivityRepository>(
+          create: (context) => ActivityRepository(),
+        ),
+        // Activity places service for Google Places API integration
+        RepositoryProvider<ActivityPlacesService>(
+          create: (context) => ActivityPlacesService(),
+        ),
         // Balance service for business logic related to balances
         RepositoryProvider<BalanceService>(
           create: (context) => BalanceService(
@@ -151,6 +162,14 @@ class MyApp extends StatelessWidget {
               expenseRepository: context.read<ExpenseRepository>(),
             ),
           ),
+          // Activity BLoC for managing trip activities
+          BlocProvider<ActivityBloc>(
+            create: (context) => ActivityBloc(
+              repository: context.read<ActivityRepository>(),
+              placesService: context.read<ActivityPlacesService>(),
+              errorService: ErrorService(),
+            ),
+          ),
         ],
         child: BlocBuilder<ThemeBloc, ThemeState>(
           builder: (context, themeState) {