refactor: 将前端从 uni-app x 重构为 Flutter

变更内容:
- 删除 uni-app x 项目 (app/ 目录)
- 新增 Flutter 项目 (flutter_monisuo/ 目录)
- 新增部署脚本 (deploy/ 目录)

Flutter 项目功能:
- 用户登录/注册
- 首页资产概览
- 行情币种列表
- 交易买卖操作
- 资产账户管理
- 充值/提现/划转
- 深色主题
- JWT Token 认证

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

flutter_monisuo/lib/data/services/user_service.dart

@@ -0,0 +1,56 @@
+import '../../core/constants/api_endpoints.dart';
+import '../../core/network/dio_client.dart';
+import '../models/user.dart';
+
+/// 用户服务
+class UserService {
+  final DioClient _client;
+
+  UserService(this._client);
+
+  /// 用户登录
+  Future<ApiResponse<Map<String, dynamic>>> login(
+    String username,
+    String password,
+  ) async {
+    return _client.post<Map<String, dynamic>>(
+      ApiEndpoints.login,
+      data: {'username': username, 'password': password},
+    );
+  }
+
+  /// 用户注册
+  Future<ApiResponse<Map<String, dynamic>>> register(
+    String username,
+    String password,
+  ) async {
+    return _client.post<Map<String, dynamic>>(
+      ApiEndpoints.register,
+      data: {'username': username, 'password': password},
+    );
+  }
+
+  /// 获取用户信息
+  Future<ApiResponse<User>> getUserInfo() async {
+    return _client.get<User>(
+      ApiEndpoints.userInfo,
+      fromJson: (data) => User.fromJson(data as Map<String, dynamic>),
+    );
+  }
+
+  /// 上传 KYC 资料
+  Future<ApiResponse<void>> uploadKyc(
+    String idCardFront,
+    String idCardBack,
+  ) async {
+    return _client.post<void>(
+      ApiEndpoints.kyc,
+      data: {'idCardFront': idCardFront, 'idCardBack': idCardBack},
+    );
+  }
+
+  /// 退出登录
+  Future<ApiResponse<void>> logout() async {
+    return _client.post<void>(ApiEndpoints.logout);
+  }
+}