fix: stabilize admin tracking event display

apps/admin-web/src/pages/AdminTrackingEventsPage.tsx

@@ -246,7 +246,7 @@ export function AdminTrackingEventsPage({
                         {formatMetadataJson(entry.metadataJson)}
                       </pre>
                     </td>
-                    <td>{entry.occurredAt || '-'}</td>
+                    <td>{formatOccurredAt(entry.occurredAt)}</td>
                     <td>
                       <button
                         className="admin-secondary-button"
@@ -314,7 +314,7 @@ function TrackingEventDetailPanel({
                     {formatMetadataJson(entry.metadataJson)}
                   </pre>
                 ) : (
-                  formatExportCell(entry[column.key]) || '-'
+                  formatExportCell(entry[column.key], column.key) || '-'
                 )}
               </dd>
             </div>
@@ -358,7 +358,10 @@ function exportTrackingEventsAsExcel(entries: AdminTrackingEventEntryPayload[])
     exportColumns.map((column) => `<th>${escapeHtml(column.label)}</th>`).join(''),
     ...entries.map((entry) =>
       exportColumns
-        .map((column) => `<td style="mso-number-format:'\\@';">${escapeHtml(formatExportCell(entry[column.key]))}</td>`)
+        .map(
+          (column) =>
+            `<td style="mso-number-format:'\\@';">${escapeHtml(formatExportCell(entry[column.key], column.key))}</td>`,
+        )
         .join(''),
     ),
   ];
@@ -376,13 +379,41 @@ function exportTrackingEventsAsExcel(entries: AdminTrackingEventEntryPayload[])
   URL.revokeObjectURL(url);
 }
 
-function formatExportCell(value: unknown) {
+function formatExportCell(value: unknown, key?: keyof AdminTrackingEventEntryPayload) {
   if (value === null || typeof value === 'undefined') {
     return '';
   }
+  if (key === 'occurredAt') {
+    return formatOccurredAt(String(value));
+  }
   return String(value);
 }
 
+function formatOccurredAt(value: string) {
+  const trimmed = value.trim();
+  if (!trimmed) {
+    return '-';
+  }
+  if (/^\d+$/.test(trimmed)) {
+    const micros = Number(trimmed);
+    if (Number.isSafeInteger(micros)) {
+      return formatDateTime(new Date(Math.floor(micros / 1000)));
+    }
+  }
+  const parsed = new Date(trimmed);
+  if (!Number.isNaN(parsed.getTime())) {
+    return formatDateTime(parsed);
+  }
+  return trimmed;
+}
+
+function formatDateTime(date: Date) {
+  const pad = (value: number, size = 2) => String(value).padStart(size, '0');
+  return `${date.getFullYear()}-${pad(date.getMonth() + 1)}-${pad(date.getDate())} ${pad(
+    date.getHours(),
+  )}:${pad(date.getMinutes())}:${pad(date.getSeconds())}`;
+}
+
 function escapeHtml(value: string) {
   return value
     .replace(/&/g, '&amp;')