feat: 对齐常驻商城与七鱼客服交互

- 同步商城 H5 登录态与原生 token
- 完善商城/原生 tab 切换、动画及返回交互
- 修复七鱼客服键盘避让和状态栏恢复
- 调整开屏跳过按钮与登录入口交互

lib/features/mall/data/mall_auth_api.dart

@@ -0,0 +1,45 @@
+import 'package:dio/dio.dart';
+import 'package:hooks_riverpod/hooks_riverpod.dart';
+
+import '../../../common/network/dio_provider.dart';
+import '../../ads/data/ads_api_client.dart';
+
+class AppMallAuthToken {
+  const AppMallAuthToken({
+    required this.authToken,
+    required this.expiresIn,
+    required this.sourceApp,
+    required this.scene,
+  });
+
+  final String authToken;
+  final int expiresIn;
+  final String sourceApp;
+  final String scene;
+}
+
+class MallAuthApi {
+  const MallAuthApi(this._dio);
+  final Dio _dio;
+
+  Future<AppMallAuthToken> issueAppMallAuthToken() async {
+    final response = await _dio.post<List<int>>(
+      '/api/v1/auth/mall/app-token',
+      data: const <int>[],
+      options: protobufOptions(),
+    );
+    final reply = ProtoMessage(response.data ?? const <int>[]);
+    final token = reply.string(1).trim();
+    if (token.isEmpty) throw const FormatException('Missing mall auth token');
+    return AppMallAuthToken(
+      authToken: token,
+      expiresIn: reply.integer(2),
+      sourceApp: reply.string(3),
+      scene: reply.string(4),
+    );
+  }
+}
+
+final mallAuthApiProvider = Provider(
+  (ref) => MallAuthApi(ref.watch(dioProvider)),
+);