BackfillEnqueueWorker re-enqueued every :queued contact each cycle, and
RadarFrameWorker had no unique clause, so the same 5-min NEXRAD frame
got scheduled repeatedly with overlapping contact lists. Prod had 9,134
duplicate available jobs across 1,061 distinct frames — 89% waste.
Two coupled changes so contacts aren't stranded by the dedup:
1. Worker now queries eligible contacts by the frame's 5-min bucket
instead of the args' contact_ids list. A contact that flips to
:queued between the enqueue and the job running gets picked up.
2. unique: [frame_ts] on states [available, scheduled, retryable].
:executing intentionally excluded — a contact that flips to :queued
mid-execution can still enqueue a follow-up instead of getting
stuck behind a running job that missed it.
Graham McIntire
ddedd241de