Prod has 0 era5_profiles rows after ~500 submit cycles: every CDS job
either gets marked "rejected" (likely cap mismatch) or runs for 13+h
without transitioning to successful, so the handle_both_done branch
has literally never fired and the ERA5Batch: stored log line has
never been emitted once. Tighten Era5PollWorker's @stuck_after_seconds
from 18h to 8h so dead rows recycle within a work shift instead of a
full day, and pause the era5 / era5_submit / era5_poll / era5_batch
queues in runtime.exs so existing rows stay put for inspection while
we figure out why CDS is rejecting everything. Flip paused: true back
once the root cause is identified.