Spots: unmatched ones matched again in turns; a standalone release gives way

A spot older than what the catalog has indexed (the spotter's first backfill
reaches back ~3 months) matched nothing and would have become a release of
its own, a duplicate once the history pass builds the upload. Unmatched
spots are matched again in turns (rematched_at) for 30 days; the 24 h before
a standalone release count from the inspection; a later match deletes the
spot's own release and links the header pass's.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

database/migrations/1770000002800_spots.ts

@@ -9,7 +9,8 @@ import { BaseSchema } from '@adonisjs/lucid/schema'
  *   (alt.binaries.ftd), keeps its files in `spot_files`, and matches them to
  *   the releases the header pass built (the same release identity), linking
  *   them in `release_spots`. A spot whose files match no release becomes a
- *   release of its own (source `spot`) once a day has passed.
+ *   release of its own (source `spot`) a day after its inspection (until
+ *   the header pass builds its releases after all: migration 2900).
  * The NZB itself is kept (gzip) for such a release's downloads.
  * Passwords are kept apart from the catalog in `release_passwords`, one row
  * per release and password, with where it came from (the NZB's meta, the