export function formatRelativeTime(dateStr: string): string {
  const date = new Date(dateStr);
  const now = new Date();
  const diffMs = now.getTime() - date.getTime();
  const diffSec = Math.floor(diffMs / 1000);
  const diffMin = Math.floor(diffSec / 60);
  const diffHour = Math.floor(diffMin / 60);
  const diffDay = Math.floor(diffHour / 24);

  if (diffSec < 60) return "just now";
  if (diffMin < 60) return `${diffMin}m ago`;
  if (diffHour < 24) return `${diffHour}h ago`;
  if (diffDay < 7) return `${diffDay}d ago`;
  return date.toLocaleDateString();
}