docs(web): unify the artist / album-artist separator hints in the editor

Both fields already accept ; and , (the backend normalizer splits on •·;,). The hints now
read uniformly — "mehrere mit ; oder , trennen" — and explain the actual difference: artist
is split into individual artists, album-artist stays one combined credit. SW ns-v61.

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

public/sw.js

@@ -1,4 +1,4 @@
-const CACHE = 'ns-v60';
+const CACHE = 'ns-v61';
 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.