/** * Compact relative timestamps for list metadata ("5m ago", "3d ago"). * * The house format is compact rather than prose ("2h ago", not "2 hours ago"), * and falls back to an absolute date once the distance stops being useful as a * relative figure. `now` is injectable so callers can test without freezing the * clock. */export const formatRelativeTime = (timestamp: number, now = Date.now()): string => {  const diffMs = Math.max(0, now - timestamp);  const minutes = Math.floor(diffMs / 60_000);  if (minutes < 1) return "just now";  if (minutes < 60) return `${minutes}m ago`;  const hours = Math.floor(minutes / 60);  if (hours < 24) return `${hours}h ago`;  const days = Math.floor(hours / 24);  if (days < 7) return `${days}d ago`;  return new Date(timestamp).toLocaleDateString(undefined, { month: "short", day: "numeric" });};