feat(socket): 添加 Socket 运行时调试日志及轮询 400 错误调试文档

- 更新 web/index.html 中 index.js 的资源版本为 v6 以清除旧缓存
- 在 web/index.js 中新增 Socket 运行时日志上报逻辑，捕获并上报连接、断开、错误及重连事件
- 新增调试文档记录生产环境 Socket.IO polling 400 错误的问题、现象与排查计划

web/index.js

@@ -38,6 +38,38 @@ createApp({
         // Prefer polling first so admin remains connected even when the proxy
         // does not support WebSocket upgrades reliably.
         const socket = io({ transports: ['polling', 'websocket'] });
+        // #region debug-point socket-runtime-admin
+        const reportSocketRuntime = (type, detail = {}) => {
+            try {
+                const payload = JSON.stringify({
+                    category: 'admin',
+                    source: 'socket-runtime',
+                    level: type.includes('error') ? 'error' : 'info',
+                    type,
+                    detail: {
+                        page: location.pathname,
+                        href: location.href,
+                        online: navigator.onLine,
+                        socket_id: socket.id || '',
+                        connected: !!socket.connected,
+                        transport: socket.io?.engine?.transport?.name || '',
+                        ...detail
+                    }
+                });
+                if (navigator.sendBeacon) {
+                    const blob = new Blob([payload], { type: 'application/json' });
+                    navigator.sendBeacon('/api/log', blob);
+                    return;
+                }
+                fetch('/api/log', {
+                    method: 'POST',
+                    headers: { 'Content-Type': 'application/json' },
+                    body: payload,
+                    keepalive: true
+                }).catch(() => {});
+            } catch (_) {}
+        };
+        // #endregion
 
         // Data State
         const stations = ref([]);
@@ -1354,8 +1386,37 @@ createApp({
         };
 
         // Socket Listeners
-        socket.on('connect', () => { connected.value = true; });
-        socket.on('disconnect', () => { connected.value = false; });
+        // #region debug-point socket-runtime-admin
+        socket.on('connect', () => {
+            connected.value = true;
+            reportSocketRuntime('socket_connect');
+        });
+        socket.on('disconnect', (reason) => {
+            connected.value = false;
+            reportSocketRuntime('socket_disconnect', { reason: reason || '' });
+        });
+        socket.on('connect_error', (error) => {
+            reportSocketRuntime('socket_connect_error', {
+                message: error?.message || '',
+                description: error?.description || '',
+                context: error?.context || null
+            });
+        });
+        if (socket.io) {
+            socket.io.on('reconnect_attempt', (attempt) => {
+                reportSocketRuntime('socket_reconnect_attempt', { attempt: Number(attempt) || 0 });
+            });
+            socket.io.on('reconnect_error', (error) => {
+                reportSocketRuntime('socket_reconnect_error', {
+                    message: error?.message || '',
+                    description: error?.description || ''
+                });
+            });
+            socket.io.on('reconnect_failed', () => {
+                reportSocketRuntime('socket_reconnect_failed');
+            });
+        }
+        // #endregion
         
         socket.on('stations:updated', (data) => { 
             stations.value = data;