fix(now-playing): split artist links and About the Artist tabs (#960)

* fix(now-playing): split artist links and About the Artist tabs

OpenSubsonic artists[] now drives per-artist navigation on Now Playing
hero and the queue current-track row (matching player bar). About the
Artist loads bio for each performer via tabs when a track has multiple
artist ids; queue Info uses the primary ref for bio/tour fetch.

Reported by zunoz on the Psysonic Discord (v1.47.0-rc.3).

* docs: note Now Playing multi-artist fix in CHANGELOG (PR #960)

src/utils/playback/trackArtistRefs.test.ts

@@ -0,0 +1,33 @@
+import { describe, expect, it } from 'vitest';
+import { primaryTrackArtistRef, resolveTrackArtistRefs } from './trackArtistRefs';
+
+describe('resolveTrackArtistRefs', () => {
+  it('prefers OpenSubsonic artists[] when present', () => {
+    const refs = [{ id: 'a1', name: 'Dan Balan' }, { id: 'a2', name: 'Katerina Begu' }];
+    expect(resolveTrackArtistRefs({
+      artist: 'Dan Balan feat. Katerina Begu',
+      artistId: 'legacy',
+      artists: refs,
+    })).toEqual(refs);
+  });
+
+  it('falls back to legacy artistId + artist', () => {
+    expect(resolveTrackArtistRefs({
+      artist: 'Solo',
+      artistId: 'ar-solo',
+    })).toEqual([{ id: 'ar-solo', name: 'Solo' }]);
+  });
+
+  it('returns name-only ref when no id', () => {
+    expect(resolveTrackArtistRefs({ artist: 'Unknown' })).toEqual([{ name: 'Unknown' }]);
+  });
+});
+
+describe('primaryTrackArtistRef', () => {
+  it('returns the first structured ref', () => {
+    expect(primaryTrackArtistRef({
+      artist: 'A feat. B',
+      artists: [{ id: 'a1', name: 'A' }, { id: 'a2', name: 'B' }],
+    })).toEqual({ id: 'a1', name: 'A' });
+  });
+});

src/utils/playback/trackArtistRefs.ts

@@ -0,0 +1,21 @@
+import type { SubsonicOpenArtistRef } from '../../api/subsonicTypes';
+import type { Track } from '../../store/playerStoreTypes';
+
+type TrackArtistFields = Pick<Track, 'artist' | 'artistId' | 'artists'>;
+
+/** OpenSubsonic `artists` when present; else legacy `artistId` + `artist` (album track rows). */
+export function resolveTrackArtistRefs(track: TrackArtistFields): SubsonicOpenArtistRef[] {
+  if (track.artists && track.artists.length > 0) {
+    return track.artists;
+  }
+  const id = track.artistId?.trim();
+  if (id) {
+    return [{ id, name: track.artist }];
+  }
+  return [{ name: track.artist }];
+}
+
+/** First performer ref — used for artist bio / discography / top songs on Now Playing. */
+export function primaryTrackArtistRef(track: TrackArtistFields): SubsonicOpenArtistRef {
+  return resolveTrackArtistRefs(track)[0];
+}