export function formatDateTime(dateStr) {
  if (!dateStr) return ''
  const d = new Date(dateStr)
  if (Number.isNaN(d.getTime())) return ''
  const yyyy = d.getFullYear()
  const mm = String(d.getMonth() + 1).padStart(2, '0')
  const dd = String(d.getDate()).padStart(2, '0')
  const hh = String(d.getHours()).padStart(2, '0')
  const mi = String(d.getMinutes()).padStart(2, '0')
  const ss = String(d.getSeconds()).padStart(2, '0')
  return `${yyyy}-${mm}-${dd} ${hh}:${mi}:${ss}`
}