implemented backend wallet service connection

frontend/pshared/lib/service/services.dart

@@ -7,6 +7,7 @@ class Services {
   static const String organization = 'organizations';
   static const String permission = 'permissions';
   static const String storage = 'storage';
+  static const String chainWallets = 'chain_wallets';
 
   static const String amplitude = 'amplitude';
   static const String clients = 'clients';

frontend/pshared/lib/service/wallet.dart

@@ -0,0 +1,31 @@
+import 'package:pshared/api/responses/wallet_balance.dart';
+import 'package:pshared/api/responses/wallets.dart';
+import 'package:pshared/data/mapper/wallet/response.dart';
+import 'package:pshared/models/wallet/balance.dart';
+import 'package:pshared/models/wallet/wallet.dart';
+import 'package:pshared/service/authorization/service.dart';
+import 'package:pshared/service/services.dart';
+
+
+class WalletService {
+  static const String _objectType = Services.chainWallets;
+
+  static Future<List<WalletModel>> list(String organizationRef) async {
+    final json = await AuthorizationService.getGETResponse(
+      _objectType,
+      '/$organizationRef',
+    );
+    return WalletsResponse.fromJson(json).toDomain();
+  }
+
+  static Future<WalletBalance> getBalance({
+    required String organizationRef,
+    required String walletRef,
+  }) async {
+    final json = await AuthorizationService.getGETResponse(
+      _objectType,
+      '/$organizationRef/$walletRef/balance',
+    );
+    return WalletBalanceResponse.fromJson(json).toDomain();
+  }
+}