Summary by cubic

Removed BullMQ from billing. Billing now writes directly to the Redis-backed batch processor, simplifying workers and improving reliability.

• Refactors
  • Removed the billing BullMQ queue, worker, and Bull Board entry.
  • scrape-worker now calls queueBillingOperation(...) instead of enqueuing a BullMQ job.
  • Kept startBillingBatchProcessing() to run the batch processor without BullMQ.

^{Written for commit0aed440. Summary will update on new commits.}