- never prune subscriptions on an empty fetch: one anomalous empty-but-200
response wiped every subscription (and its deep_requested flag) in one run
- push_playlist: stop after 5 consecutive write failures — a quota-dead or
scope-revoked account otherwise burns 50 units per remaining item
- RSS: raise RssError instead of returning [] on a transport/HTTP failure, so a
failed poll no longer stamps last_rss_at and a 404 feed stops looking healthy
- worker: exit when the schema never appears instead of "continuing" into a
crash one call later