Fix timestamp timezone: treat backend UTC datetimes as UTC, display in browser local time

frontend/src/components/HistoryPanel.tsx

@@ -23,8 +23,8 @@ const statusColor = {
 }
 
 function formatDate(dt: string) {
-  const d = new Date(dt)
-  return d.toLocaleDateString('en-US', { month: 'short', day: 'numeric', hour: 'numeric', minute: '2-digit' })
+  const utc = dt.endsWith('Z') || dt.includes('+') ? dt : dt + 'Z'
+  return new Date(utc).toLocaleString(undefined, { month: 'short', day: 'numeric', hour: 'numeric', minute: '2-digit' })
 }
 
 export default function HistoryPanel({ runs, currentRunId, onSelect }: Props) {

frontend/src/pages/Dashboard.tsx

@@ -136,7 +136,9 @@ export default function Dashboard() {
 
   const formatRunTime = (dt: string | null) => {
     if (!dt) return ''
-    return new Date(dt).toLocaleString('en-US', {
+    // Ensure UTC is interpreted correctly (backend returns naive ISO without Z)
+    const utc = dt.endsWith('Z') || dt.includes('+') ? dt : dt + 'Z'
+    return new Date(utc).toLocaleString(undefined, {
       weekday: 'short', month: 'short', day: 'numeric',
       hour: 'numeric', minute: '2-digit',
     })