fix：优化和对齐版本

lib/common/storage/secure_identity_storage.dart

@@ -0,0 +1,21 @@
+import 'package:flutter_secure_storage/flutter_secure_storage.dart';
+import 'package:hooks_riverpod/hooks_riverpod.dart';
+
+const _jwtKey = 'jwt_token';
+
+/// Sensitive identity values stay behind one injectable storage boundary.
+class SecureIdentityStorage {
+  SecureIdentityStorage({FlutterSecureStorage? storage})
+    : _storage = storage ?? const FlutterSecureStorage();
+
+  final FlutterSecureStorage _storage;
+
+  Future<void> saveJwt(String token) =>
+      _storage.write(key: _jwtKey, value: token);
+  Future<void> clearJwt() => _storage.delete(key: _jwtKey);
+  Future<String?> readJwt() => _storage.read(key: _jwtKey);
+}
+
+final secureIdentityStorageProvider = Provider<SecureIdentityStorage>(
+  (ref) => SecureIdentityStorage(),
+);