fix: 优化飞书内免登功能，移除外部 JSBridge SDK 加载

- tt 对象由飞书客户端自动注入，无需加载外部 SDK
- 增加轮询超时时间到 10 秒
- 添加更详细的调试日志
- 超时时降级到扫码登录

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

frontend/index.html

@@ -5,49 +5,9 @@
     <link rel="icon" type="image/svg+xml" href="/vite.svg" />
     <meta name="viewport" content="width=device-width, initial-scale=1.0" />
     <title>frontend</title>
-    <!-- 飞书扫码登录 SDK -->
+    <!-- 飞书扫码登录 SDK（飞书外扫码登录用） -->
     <script src="https://lf-package-cn.feishucdn.com/obj/feishu-static/lark/passport/qrcode/LarkSSOSDKWebQRCode-1.0.3.js"></script>
-    <!-- 飞书 H5 JSBridge SDK（多 CDN 备用） -->
-    <script>
-      // 尝试加载飞书 JSBridge，如果失败则尝试其他 CDN
-      var scripts = [
-        'https://lf1-cdn-tos.bytegoofy.com/goofy/lark/passport/h5-jsbridge-1.0.3.js',
-        'https://lf9-cn.feishucdn.com/obj/lark/passport/h5-jsbridge-1.0.3.js'
-      ];
-
-      function loadScript(url) {
-        return new Promise(function(resolve, reject) {
-          var script = document.createElement('script');
-          script.src = url;
-          script.onload = function() { console.log('JSBridge loaded from:', url); resolve(); };
-          script.onerror = function() { reject(url); };
-          document.head.appendChild(script);
-        });
-      }
-
-      // 按顺序尝试加载 JSBridge
-      function loadJSBridge() {
-        var index = 0;
-        function tryNext() {
-          if (index < scripts.length) {
-            loadScript(scripts[index])
-              .catch(function() {
-                console.warn('JSBridge load failed:', scripts[index]);
-                index++;
-                tryNext();
-              });
-          } else {
-            console.error('All JSBridge CDNs failed');
-          }
-        }
-        tryNext();
-      }
-
-      // 页面加载后尝试加载 JSBridge
-      if (navigator.userAgent.includes('Lark') || navigator.userAgent.includes('feishu')) {
-        loadJSBridge();
-      }
-    </script>
+    <!-- 飞书内免登说明：tt 对象由飞书客户端自动注入，无需加载外部 SDK -->
   </head>
   <body>
     <div id="root"></div>