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
- Added ExpenseDetailDialog for displaying expense details and actions.
- Created ExpensesTab to list expenses for a group.
- Developed GroupExpensesPage to manage group expenses with tabs for expenses, balances, and settlements.
- Introduced SettlementsTab to show optimized repayment plans.
- Refactored create_trip_content.dart to remove CountBloc and related logic.
- Added Account model to manage user accounts and group members.
- Replaced CountRepository with AccountRepository for account-related operations.
- Removed CountService and CountRepository as part of the refactor.
- Updated main.dart and home.dart to integrate new account management components.
