- Provider fetches all release groups via paginated browse, no type filter
- Service caches all albums in DB, ensures referenced artists exist first
- Server handler filters by album_types (default: album|ep|single), excludes secondary types
- Add secondary_types to domain, DB schema, and MB types
- Add ErrBadRequest handling for MusicBrainz 400 errors
- Replace migrations with single schema.sql
- Add GetAllByArtistID and SaveAll to album repository
- gRPC service with MusicBrainz provider
- PostgreSQL schema with migrations
- Service layer with database-first caching
- Repository pattern for data access
- YAML configuration support
- Research documentation for 17 music metadata projects