fix: 前端追踪时间 — 三处toISOString()全部替换为本地时间

- traceHopHtml 直接用后端格式化好的 timestamp
- llmCallToTrace 用前端 fmtLocal()
- 实时流事件用本地时间格式化

ethend/public/index.html

@@ -6109,7 +6109,7 @@ async function renderVMMonitorPanel() {
 
     for (var i = 0; i < allCalls.length; i++) {
       var call = allCalls[i];
-      var ts = new Date(call.timestamp / 1e6).toISOString().replace('T', ' ').slice(0, 19);
+      var d = new Date(call.timestamp / 1e6); var ts = d.getFullYear()+'-'+String(d.getMonth()+1).padStart(2,'0')+'-'+String(d.getDate()).padStart(2,'0')+' '+String(d.getHours()).padStart(2,'0')+':'+String(d.getMinutes()).padStart(2,'0')+':'+String(d.getSeconds()).padStart(2,'0');
       var successIcon = call.success ? '✅' : '❌';
       var args = {};
       try { args = JSON.parse(call.arguments || '{}'); } catch(e) {}
@@ -6142,6 +6142,7 @@ async function renderVMMonitorPanel() {
 }
 
 // ========== 全链路追踪面板 ==========
+function fmtLocal(ts) { var d = new Date(ts); var p = function(n) { return n < 10 ? '0' + n : '' + n; }; return d.getFullYear() + '-' + p(d.getMonth()+1) + '-' + p(d.getDate()) + ' ' + p(d.getHours()) + ':' + p(d.getMinutes()) + ':' + p(d.getSeconds()); }
 var traceMode = 'recent'; // 'recent' | 'session'
 var traceSessionId = '';
 var traceStreamSource = null;
@@ -6372,7 +6373,7 @@ function pruneTimeline() {
 }
 
 function traceHopHtml(t, prevT) {
-  var time = new Date(t.timestamp).toISOString().replace('T', ' ').slice(0, 19);
+  var time = t.timestamp; // already local time from backend
   var isError = t.status === 'error';
   var gapHtml = '';
 
@@ -6425,7 +6426,7 @@ function llmCallToTrace(call) {
   var ts = call.time ? new Date(call.time).getTime() : Date.now();
   return {
     id: 'llm-' + ts + '-' + Math.random().toString(36).slice(2, 6),
-    timestamp: new Date(ts).toISOString(),
+    timestamp: fmtLocal(ts),
     ts: ts,
     service: 'ai-core',
     hop: 'llm_call',