修复实例页长时间后不自动刷新：回前台强制拉数、SSE假连接兜底、快照请求超时防卡死。

Co-authored-by: Cursor <cursoragent@cursor.com>

lib/instance/templates/embed_boot_scripts.html

@@ -1173,6 +1173,17 @@ function accountSnapshotFundingMissing(data){
     return !hasFunding && !hasTotal && !hasTrading;
 }
 let accountSnapshotRetryCount = 0;
+let accountSnapshotInflight = false;
+let priceSnapshotInflight = false;
+
+function fetchJsonWithTimeout(url, timeoutMs) {
+  const ms = timeoutMs != null ? timeoutMs : 25000;
+  const ac = new AbortController();
+  const timer = setTimeout(function () { ac.abort(); }, ms);
+  return fetch(url, { signal: ac.signal, credentials: "same-origin" })
+    .then(function (r) { return r.json(); })
+    .finally(function () { clearTimeout(timer); });
+}
 function applyAccountSnapshot(data){
     if(!data || typeof data !== "object") return;
     if(typeof data.show_perp_funds !== "undefined"){
@@ -1263,8 +1274,10 @@ function applyAccountSnapshot(data){
 }
 function refreshAccountSnapshot(opts){
     const options = opts || {};
+    if(accountSnapshotInflight && !options.force) return;
+    accountSnapshotInflight = true;
     const qs = options.force ? "?force=1" : "";
-    fetch("/api/account_snapshot" + qs).then(r=>r.json()).then(data=>{
+    fetchJsonWithTimeout("/api/account_snapshot" + qs, 25000).then(data=>{
         applyAccountSnapshot(data);
         if(accountSnapshotFundingMissing(data) && !options.force && accountSnapshotRetryCount < 3){
             accountSnapshotRetryCount += 1;
@@ -1277,7 +1290,7 @@ function refreshAccountSnapshot(opts){
             accountSnapshotRetryCount += 1;
             setTimeout(() => refreshAccountSnapshot({ silent: true }), 1200 * accountSnapshotRetryCount);
         }
-    });
+    }).finally(()=>{ accountSnapshotInflight = false; });
 }
 
 const orderSymbolEl = document.getElementById("order-symbol");
@@ -1419,8 +1432,10 @@ refreshOrderDefaults();
 if(typeof initOrderEntryModelSelect === "function") initOrderEntryModelSelect();
 refreshPriceSnapshotConditional();
 function refreshPriceSnapshotConditional(){
+    if(priceSnapshotInflight) return;
+    priceSnapshotInflight = true;
     const page = document.body.getAttribute("data-page") || "";
-    fetch("/api/price_snapshot").then(r=>r.json()).then(data=>{
+    fetchJsonWithTimeout("/api/price_snapshot", 25000).then(data=>{
         const updatedEl = document.getElementById("price-last-updated");
         if(data.updated_at && updatedEl) updatedEl.innerText = data.updated_at;
         if(data.force_close && window.TimeCloseUI && TimeCloseUI.paintForceCloseHeader){
@@ -1474,7 +1489,7 @@ function refreshPriceSnapshotConditional(){
         } else if (typeof data.options_unrealized_pnl !== "undefined") {
             paintRealtimePnlFromSnapshot(data);
         }
-    }).catch(()=>{});
+    }).catch(()=>{}).finally(()=>{ priceSnapshotInflight = false; });
 }
 function formatLiveHoldDurationFromMs(openedMs, nowMs){
     if(openedMs == null || openedMs === "" || !Number.isFinite(Number(openedMs))) return "—";