Cache maintenance:
- Input validation rejects junk entities (Unknown Artist, empty names)
from being cached, with exemptions for synthetic entries (_features,
_tracks suffixes)
- CacheEvictorJob expanded to 4 phases: TTL eviction, junk cleanup,
orphaned search cleanup, MusicBrainz failed lookup cleanup
- MusicBrainz null results now expire after 30 days (was 90) so failed
lookups get retried sooner
Cache health UI:
- Polished modal accessible from Dashboard "Cache Health" button and
repair dashboard health bar
- Shows health status banner (healthy/fair/poor), stat cards, source
breakdown with colored progress bars, type pills, and metrics table
- Repair dashboard shows compact bar with health dot indicator
