1. GridCache: auto-release fill lock when the claimer process crashes.
claim_fill/1 + release_fill/1 go through the GenServer so the
server can Process.monitor the caller and clean up the ETS entry
on :DOWN. Clear/0 now resets both the data table and the lock
table. Fixes a latent bug where a crashed fill leaked the lock
indefinitely, preventing every subsequent /weather mount for that
valid_time from claiming and leaving cache cold.
2. RadarFrameWorker: distinguish permanent vs transient fetch errors.
404 from the IEM n0q archive is permanent (file will never exist)
and marks contacts :unavailable as before. Any other error shape
(5xx, timeout, transport failure) now returns {:error, reason}
so Oban retries — previously those also pinned contacts at
:unavailable after a transient outage.
3. AdminTaskWorker.native_derive: replace per-row Repo.update_all
(N round-trips + N fsyncs) with one UPDATE ... FROM unnest(...)
per 2000-row batch. For the 10k-profile budget this is one
network round trip per chunk instead of 10k, and one fsync per
chunk instead of 10k. Restructured the clause to separate
derivation (pure) from persistence (I/O).
All three changes are test-covered (grid_cache_test auto-release
test, radar_frame_worker_test 5xx + transport tests, existing
admin_task_worker_test native_derive coverage exercises the new
bulk path). Also drops the scorer_diff no-op test that was
verifying the clause removed in 61da51c.
Graham McIntire
7b78a2574c