Implement BullMQ job workflows in NestJS. Use when building queue processors, redis-throttler, Upstash limits, idle polling, stalled jobs, and retention policies. (triggers: **/*.processor.ts, **/*.module.ts, **/bull-queue.constants.ts, **/redis-throttler*.ts, queue, background job, worker, processor, bullmq, drainDelay, stalledInterval, removeOnComplete, redis limit, upstash, fail-open, throttler)