formatQuotaReset function
Reset countdown: '' when unknown, reset overdue in the past (E4),
otherwise the coarsest nonzero unit (11d / 5h / 3m / <1m).
Implementation
String formatQuotaReset(DateTime? resetsAt, DateTime now) {
if (resetsAt == null) return '';
if (!now.isBefore(resetsAt)) return 'reset overdue';
final delta = resetsAt.difference(now);
if (delta.inDays >= 1) return '${delta.inDays}d';
if (delta.inHours >= 1) return '${delta.inHours}h';
if (delta.inMinutes >= 1) return '${delta.inMinutes}m';
return '<1m';
}