feat: refactor code

lib/feature/auth/data/data_source/local/auth_local_data.dart

@@ -0,0 +1,16 @@
+import '../../../../../core/storage/token_storage.dart';
+
+/// ذخیره‌ی محلیِ توکن احراز هویت.
+class AuthLocalData {
+  final TokenStorage _storage;
+  AuthLocalData(this._storage);
+
+  Future<void> saveToken(String token) => _storage.write(token);
+  Future<String?> readToken() => _storage.read();
+  Future<void> clearToken() => _storage.clear();
+
+  Future<bool> hasToken() async {
+    final t = await _storage.read();
+    return t != null && t.isNotEmpty;
+  }
+}