export function timeAgo(dateStr: string): string {
  if (!dateStr) return "";
  const date = new Date(dateStr);
  if (isNaN(date.getTime())) return "";
  const now = new Date();
  const diffMs = now.getTime() - date.getTime();
  const diffSec = Math.floor(diffMs / 1000);
  if (diffSec < 60) return "just now";
  const diffMin = Math.floor(diffSec / 60);
  if (diffMin < 60) return `${diffMin}m ago`;
  const diffHr = Math.floor(diffMin / 60);
  if (diffHr < 24) return `${diffHr}h ago`;
  const diffDay = Math.floor(diffHr / 24);
  return `${diffDay}d ago`;
}