retryDeadLetter method
Retries a dead-letter job by its jobId, moving it back to the queue.
Implementation
@override
Future<bool> retryDeadLetter(String jobId) async {
final idx = _failed.indexWhere((j) => j.id == jobId);
if (idx == -1) return false;
final job = _failed.removeAt(idx);
job.status = JobStatus.pending;
job.attempts = 0;
job.lastError = null;
job.lastStackTrace = null;
job.availableAt = null;
job.finishedAt = null;
_queue(job.queue).add(job);
return true;
}