fix: 修复飞书内免登功能

- 动态加载飞书 JSBridge SDK（多 CDN 备用）
- 等待 tt 对象加载后尝试免登
- 超时后降级为二维码登录

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

frontend/index.html

@@ -7,6 +7,47 @@
     <title>frontend</title>
     <!-- 飞书扫码登录 SDK -->
     <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>
   </head>
   <body>
     <div id="root"></div>