feat: Add User and UserBalance models with serialization methods

feat: Implement BalanceRepository for group balance calculations

feat: Create ExpenseRepository for managing expenses

feat: Add services for handling expenses and storage operations

fix: Update import paths for models in repositories and services

refactor: Rename CountContent to AccountContent in HomePage

chore: Add StorageService for image upload and management

lib/blocs/auth/auth_state.dart

@@ -1,5 +1,5 @@
 import 'package:equatable/equatable.dart';
-import '../../data/models/user.dart';
+import '../../models/user.dart';
 
 abstract class AuthState extends Equatable {
   const AuthState();