Enhance frontend documentation and UI components; update frontend-shadcn.mdc to include UI patterns reference; improve navigation structure in AppSidebar by categorizing items; refactor DataTableCard to support empty states with EmptyState component; implement ConfirmDialog for delete actions in DnsRecordsTable and GroupsPage; add search functionality in CertificatesPage and GroupsPage for better user experience; update ServiceEditSheet to utilize tabs for organization.

apps/web/src/lib/format.ts

@@ -0,0 +1,31 @@
+const dateFormatter = new Intl.DateTimeFormat('ru-RU', {
+  dateStyle: 'medium',
+  timeStyle: 'short',
+})
+
+const relativeFormatter = new Intl.RelativeTimeFormat('ru', { numeric: 'auto' })
+
+export function formatDate(iso: string | null | undefined): string {
+  if (!iso) return '—'
+  const date = new Date(iso)
+  if (Number.isNaN(date.getTime())) return iso
+  return dateFormatter.format(date)
+}
+
+export function formatRelative(iso: string | null | undefined): string {
+  if (!iso) return '—'
+  const date = new Date(iso)
+  if (Number.isNaN(date.getTime())) return iso
+  const diffMs = date.getTime() - Date.now()
+  const diffSec = Math.round(diffMs / 1000)
+  const absSec = Math.abs(diffSec)
+
+  if (absSec < 60) return relativeFormatter.format(diffSec, 'second')
+  const diffMin = Math.round(diffSec / 60)
+  if (Math.abs(diffMin) < 60) return relativeFormatter.format(diffMin, 'minute')
+  const diffHour = Math.round(diffMin / 60)
+  if (Math.abs(diffHour) < 24) return relativeFormatter.format(diffHour, 'hour')
+  const diffDay = Math.round(diffHour / 24)
+  if (Math.abs(diffDay) < 30) return relativeFormatter.format(diffDay, 'day')
+  return formatDate(iso)
+}