Three domain-eng modules peel ~316 LOC of fetch/mapping out of
`api/subsonic.ts`:
- `subsonicLibrary.ts` — browse + random + per-song fetch
(`getMusicDirectory`, `getMusicIndexes`, `getMusicFolders`,
`getRandomAlbums`, `getAlbumList`, `getRandomSongs`,
`getRandomSongsFiltered`, `getSong`, `getAlbum`,
`filterSongsToActiveLibrary`, `similarSongsRequestCount`, plus
the private `albumIdsInActiveLibraryScope` cache).
- `subsonicArtists.ts` — artist endpoints (`getArtists`, `getArtist`,
`getArtistInfo`, `getTopSongs`, `getSimilarSongs2`,
`getSimilarSongs`). Uses Library's `filterSongsToActiveLibrary` and
`similarSongsRequestCount` for the per-library scoping fallback.
- `subsonicRatings.ts` — `parseSubsonicEntityStarRating` parser plus
`prefetchArtistUserRatings` and `prefetchAlbumUserRatings` workers
with the shared 7-min cache. Calls back into Library/Artists for
the per-id fetch.
51 external call sites migrated to direct imports. No re-export
shims in `subsonic.ts`. Statistics endpoints still in `subsonic.ts`
keep their `RATING_CACHE_TTL` constant locally (same 7-min window).
subsonic.ts: 1078 → 762 LOC (−316).
Frank Stellmacher