feat(artist pin): pin by Deezer link/ID when search can't surface the artist

Deezer's /search/artist is a ranked, incomplete fuzzy match — low-profile
same-name artists (e.g. Nana id 80239872) never appear in results. Add a
"paste Deezer link or ID" field to the pin picker that looks the artist up
directly via /artist/{id} (new deezerLookupArtist) and pins it. Same reliable
route as the importer direct link vs yt-dlp search.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

public/sw.js

@@ -1,4 +1,4 @@
-const CACHE = 'ns-v75';
+const CACHE = 'ns-v76';
 const PRECACHE = ['/', 'index.html', 'manifest.json', 'icon.svg'];
 const SKIP_PATHS = ['/rest/stream', '/rest/download', '/config.js'];
 // Auth token params stripped from cache keys so artwork survives across sessions/token refreshes.