feat: Implement group balance and expense management with new navigation and data handling

lib/blocs/balance/balance_state.dart

@@ -1,5 +1,6 @@
 import 'package:equatable/equatable.dart';
-import '../../models/group_balance.dart';
+import '../../models/settlement.dart';
+import '../../models/user_balance.dart';
 
 abstract class BalanceState extends Equatable {
   const BalanceState();
@@ -12,13 +13,17 @@ class BalanceInitial extends BalanceState {}
 
 class BalanceLoading extends BalanceState {}
 
-class BalanceLoaded extends BalanceState {
-  final GroupBalance groupBalance;
-
-  const BalanceLoaded(this.groupBalance);
-
+class GroupBalancesLoaded extends BalanceState {
+  final List<UserBalance> balances;
+  final List<Settlement> settlements;
+  
+  const GroupBalancesLoaded({
+    required this.balances,
+    required this.settlements,
+  });
+  
   @override
-  List<Object?> get props => [groupBalance];
+  List<Object> get props => [balances, settlements];
 }
 
 class BalanceOperationSuccess extends BalanceState {