diff --git a/debug-socket-polling-400.md b/debug-socket-polling-400.md
new file mode 100644
index 0000000..71fe293
--- /dev/null
+++ b/debug-socket-polling-400.md
@@ -0,0 +1,26 @@
+# [OPEN] debug-socket-polling-400
+
+## 问题描述
+- 生产环境后台页持续出现 Socket.IO polling 400。
+- 浏览器控制台可见大量：
+  - `GET /socket.io/?EIO=4&transport=polling&sid=... 400`
+  - `POST /socket.io/?EIO=4&transport=polling&sid=... 400`
+- 同时存在无关但可观察现象：
+  - `vue.global.js` 开发版提示
+  - `/favicon.ico` 404
+
+## 已知现象
+- 首次 `polling` 握手能拿到 `sid`，后续带 `sid` 的轮询请求失败。
+- 失败后客户端持续重连，表现为“连接一下又断开”。
+
+## 初始假设
+- 假设 1：反向代理或负载均衡未做会话保持，导致同一个 `sid` 的后续请求落到不同后端实例。
+- 假设 2：CDN/边缘代理对 `/socket.io/` 的长轮询处理不稳定，导致 `sid` 生命周期被中断。
+- 假设 3：客户端当前传输策略触发了不兼容的重连路径，反复创建新 `sid` 又迅速失效。
+- 假设 4：服务端 Engine.IO 对同一会话的请求顺序或超时异常敏感，导致后续 `GET/POST` 被判无效。
+- 假设 5：`vue.global.js` 开发版提示和 `favicon.ico` 404 只是噪音，不是 Socket.IO 400 的主因。
+
+## 当前计划
+- 先继续收集线上现成证据，不改业务逻辑。
+- 对比首次握手与后续 `sid` 请求是否稳定落到同一服务链路。
+- 若证据仍指向服务端/代理层，再决定是否做最小客户端降级或服务端兼容修复。
diff --git a/web/index.html b/web/index.html
index 6777331..438b672 100644
--- a/web/index.html
+++ b/web/index.html
@@ -1,4 +1,4 @@
-﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿<!DOCTYPE html>
+﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿﻿<!DOCTYPE html>
 <html lang="zh-CN">
 <!-- 充满未知和不稳定的票务系统！ -->
 
@@ -933,7 +933,7 @@
     </div>
     <script src="/custom-dialog.js?v=12"></script>
     <script src="/public-status.js?v=13"></script>
-    <script src="index.js?v=5"></script>
+    <script src="index.js?v=6"></script>
     <script>
         document.addEventListener('DOMContentLoaded', () => {
             const isDomain = location.hostname.includes('fse-media.group');
diff --git a/web/index.js b/web/index.js
index 7b1c206..bfe2888 100644
--- a/web/index.js
+++ b/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; 
