style: two-line Started column (date over time) in session list

Narrows the column so more columns fit on one page; matches the
two-line style of Device/Model/Status cells.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/Web/autopilot-monitor-web/app/dashboard/components/SessionTable.tsx

@@ -885,12 +885,16 @@ function SessionCell({
         </td>
       );
 
-    case "started":
+    case "started": {
+      // Two-line date/time keeps the column narrow so more columns fit on one page.
+      const started = new Date(session.startedAt);
       return (
         <td className="px-3 py-4 whitespace-nowrap text-sm text-gray-500">
-          {new Date(session.startedAt).toLocaleString()}
+          <div>{started.toLocaleDateString()}</div>
+          <div className="text-xs text-gray-400">{started.toLocaleTimeString()}</div>
         </td>
       );
+    }
 
     case "country":
       return (