Apple's iTunes /search returns 403 from server IPs, killing the Erkunden search. Deezer
is free, needs no key, and is actually better: it returns explicit versions, artist
images, track durations and 30s previews.
- Backend: /api/deezer/* proxy (CORS-safe); album download accepts a `tracks` array in
the request body (Deezer albums send their tracks directly, pre-mapped).
- api.js: itunesSearch / itunesLookupAlbum / itunesLookupArtistSongs|Albums now hit
Deezer and map results to the existing ItunesItem shape, so the UI + download flow are
unchanged. Function names kept.
- downloads.js: album downloads fetch the Deezer album's tracks and send them in the body.
iTunes /lookup (by ID) and the charts RSS proxy stay. Known follow-ups: artist-type
download still calls iTunes /search server-side; the metadata-editor iTunes autofill;
and the Android client — all still on iTunes for now.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>