Spotify was being called for album/artist data fetching across multiple
background workers and the Artists page search even when the user had
Deezer or iTunes set as their primary metadata source. Being authenticated
for playlist sync was treated as permission to use Spotify for everything.
- watchlist_scanner: add _spotify_is_primary_source() that checks both
auth and primary source config; use it for all album/artist data fetching
(discovery pool, recent album caching, playlist curation, similar artist
ID matching, proactive ID backfill). _spotify_available_for_run() is kept
for sync_spotify_library_cache which must run regardless of primary source
- repair_jobs/metadata_gap_filler: gate Spotify ISRC lookup on primary
source being 'spotify'; MusicBrainz lookup unaffected
- repair_jobs/unknown_artist_fixer: replace hardcoded spotify_client with
source-aware client selection — primary source ID tried first, each ID
matched to its correct client (fixes latent bug passing Deezer IDs to
Spotify)
- web_server.py /api/match/search: Artists page search was hardcoded to
spotify_client.search_artists(); now uses _get_metadata_fallback_client()
so results come from the configured primary source