feat(monitor): show commit timestamps in updates tab

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/pages/AdminMonitor.tsx

@@ -7,12 +7,24 @@ interface AppStatus {
   repo: string
   host: string
   currentCommit: string
+  currentCommitAt: string | null
   latestCommit: string
+  latestCommitAt: string | null
   updateAvailable: boolean
   deployed: boolean
   checkedAt: string
 }
 
+function relativeTime(iso: string | null | undefined): string | null {
+  if (!iso) return null
+  const diff = Date.now() - new Date(iso).getTime()
+  if (diff < 60_000) return 'just now'
+  if (diff < 3_600_000) return `${Math.floor(diff / 60_000)}m ago`
+  if (diff < 86_400_000) return `${Math.floor(diff / 3_600_000)}h ago`
+  if (diff < 7 * 86_400_000) return `${Math.floor(diff / 86_400_000)}d ago`
+  return new Date(iso).toLocaleDateString(undefined, { day: 'numeric', month: 'short' })
+}
+
 interface HealthStatus {
   name: string
   up: boolean
@@ -172,8 +184,20 @@ export function AdminMonitor({ user }: { user: User }) {
                     </div>
                     <div style={{ fontSize: '0.72rem', color: 'var(--text-mid)', fontFamily: 'monospace' }}>
                       {s.deployed ? `deployed: ${s.currentCommit}` : s.currentCommit}
+                      {s.deployed && relativeTime(s.currentCommitAt) && (
+                        <span style={{ marginLeft: '0.35rem', fontFamily: 'sans-serif', opacity: 0.7 }}>
+                          · {relativeTime(s.currentCommitAt)}
+                        </span>
+                      )}
                       {s.latestCommit !== 'unknown' && (
-                        <span style={{ marginLeft: '0.75rem' }}>latest: {s.latestCommit}</span>
+                        <span style={{ marginLeft: '0.75rem' }}>
+                          latest: {s.latestCommit}
+                          {relativeTime(s.latestCommitAt) && (
+                            <span style={{ marginLeft: '0.35rem', fontFamily: 'sans-serif', opacity: 0.7 }}>
+                              · {relativeTime(s.latestCommitAt)}
+                            </span>
+                          )}
+                        </span>
                       )}
                     </div>
                   </div>