/** Stable server time, with the full local date available to keyboard and assistive readers. */
export function MessageTimestamp({ value }: { value?: string }) {
  const date = value ? new Date(value) : null
  if (!date || !Number.isFinite(date.getTime())) return null
  const full = date.toLocaleString('zh-CN', { year: 'numeric', month: '2-digit', day: '2-digit', hour: '2-digit', minute: '2-digit', second: '2-digit', hour12: false })
  const label = date.toLocaleTimeString('zh-CN', { hour: '2-digit', minute: '2-digit', hour12: false })
  return <time className="message-timestamp" dateTime={date.toISOString()} title={full} aria-label={full}>{label}</time>
}