- Fix duplicate Telegram notifications: SyncArtistDiscography no longer wipes
notifications_sent for the whole artist on every cache-miss re-sync; only
markers for releases that disappear are pruned (FK-safe via INSERT OR REPLACE
+ rgid NOT IN (...)).
- Cache empty MusicBrainz discographies via a new artist_settings.last_synced
column (migration 009) so zero-release artists honor the TTL instead of being
re-fetched every cycle.
- Wire the Web UI server and Telegram notifier scheduler into main.run/NewApp.
- Guard startPeriodicSync against overlapping syncs with a done-channel slot.
- Add server.public_url config; NewServerWithConfig derives reachable links
and no longer advertises the 0.0.0.0 bind address.
- Web handlers: use scanner.ScanArtist per artist, drop always-false
releaseIgnored lookup and dead endsWith, thread configured threshold.
- Limit :memory: DB pool to one connection so migrations and queries share the
same in-memory store.
Implements Task 8: artist detail page (local albums + found-missing
with ignore buttons), ignored-releases archive with restore, and POST
handlers toggling ignore flags and ignore_singles. Adds ErrArtistNotFound
sentinel so callers can distinguish missing artists, and wires routes via
the enhanced ServeMux path wildcard.
