fix(ui): split album and track artists (OpenSubsonic) (#696)

* fix(ui): split OpenSubsonic album and track artists in header and player

Album detail header uses albumArtists from album or child songs; player bar,
mobile player, and mini player use structured track artists with per-id links.
Adds deriveAlbumHeaderArtistRefs helper and OpenArtistRefInline.

Fixes #552

* docs: changelog and credits for OpenSubsonic artist links (PR #696)

src/utils/album/deriveAlbumHeaderArtistRefs.test.ts

@@ -0,0 +1,46 @@
+import { describe, expect, it } from 'vitest';
+import { deriveAlbumHeaderArtistRefs } from './deriveAlbumHeaderArtistRefs';
+import type { SubsonicAlbum } from '../../api/subsonicTypes';
+import { makeSubsonicSong } from '@/test/helpers/factories';
+
+const baseAlbum = (): SubsonicAlbum => ({
+  id: 'al-1',
+  name: 'Test Album',
+  artist: 'Joined A / B',
+  artistId: 'ar-first',
+  songCount: 2,
+  duration: 100,
+});
+
+describe('deriveAlbumHeaderArtistRefs', () => {
+  it('prefers album-level albumArtists when present', () => {
+    const album: SubsonicAlbum = {
+      ...baseAlbum(),
+      albumArtists: [{ id: 'a1', name: 'One' }, { id: 'a2', name: 'Two' }],
+    };
+    expect(deriveAlbumHeaderArtistRefs(album, [])).toEqual(album.albumArtists);
+  });
+
+  it('falls back to the first song with albumArtists', () => {
+    const album = baseAlbum();
+    const songs = [
+      makeSubsonicSong({
+        albumId: album.id,
+        album: album.name,
+        albumArtists: [{ id: 'b1', name: 'Beta' }, { name: 'Gamma' }],
+      }),
+    ];
+    expect(deriveAlbumHeaderArtistRefs(album, songs)).toEqual(songs[0].albumArtists);
+  });
+
+  it('uses legacy artist + artistId when no structured refs', () => {
+    const album = baseAlbum();
+    const songs = [makeSubsonicSong({ albumId: album.id, album: album.name })];
+    expect(deriveAlbumHeaderArtistRefs(album, songs)).toEqual([{ id: 'ar-first', name: 'Joined A / B' }]);
+  });
+
+  it('omits id when artistId is blank', () => {
+    const album: SubsonicAlbum = { ...baseAlbum(), artistId: '   ', artist: 'Solo' };
+    expect(deriveAlbumHeaderArtistRefs(album, [])).toEqual([{ name: 'Solo' }]);
+  });
+});