feat: fans on local Navidrome artists (android) + harmonize web fan layout

- Android local artist page (ArtistDetailScreen/ArtistViewModel) now resolves the Deezer
  artist (fan-sorted, so same-name collisions pick the popular one) and shows "<n> Fans"
  under the name — parity with the web local artist page.
- Also migrated ArtistViewModel's preview to the app-level PreviewController: the local
  artist page had its OWN uncontrollable MediaPlayer preview, which had the same
  "keeps playing after navigating away" bug. Now every preview uses the global bar.
- Web: the artist-hero fan line was laid out in a row next to the name (flex without
  column direction) and used an odd tinted color — now stacked cleanly under the name in
  a muted white. SW ns-v54.
- CHANGELOG: documented the above + added a Known Bug (Android synced-lyrics auto-scroll
  still doesn't follow playback).

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

styles.css

@@ -846,9 +846,9 @@ button:focus{outline:none}
 .artist-hero-pfp-wrap{aspect-ratio:1/1;height:100%;flex-shrink:0;overflow:hidden;position:relative;background:linear-gradient(135deg,var(--surface2),var(--surface3,var(--surface)))}
 .artist-hero-pfp{position:absolute;inset:0;width:100%;height:100%;object-fit:cover;display:block}
 .artist-hero-pfp-initial{position:absolute;inset:0;display:flex;align-items:center;justify-content:center;font-size:52px;font-weight:700;color:var(--text2);line-height:1}
-.artist-hero-info{min-width:0;flex:1;display:flex;align-items:flex-end;padding:20px 24px;background:linear-gradient(to left,rgba(7,7,15,.95) 0%,rgba(7,7,15,.1) 100%)}
-.artist-hero-name{font-size:26px;font-weight:800;letter-spacing:-0.5px;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
-.artist-hero-fans{font-size:12px;font-weight:600;color:var(--text2);margin-top:3px;display:none}
+.artist-hero-info{min-width:0;flex:1;display:flex;flex-direction:column;justify-content:flex-end;align-items:flex-start;padding:20px 24px;background:linear-gradient(to left,rgba(7,7,15,.95) 0%,rgba(7,7,15,.1) 100%)}
+.artist-hero-name{max-width:100%;font-size:26px;font-weight:800;letter-spacing:-0.5px;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
+.artist-hero-fans{font-size:13px;font-weight:600;color:rgba(255,255,255,.58);margin-top:6px;letter-spacing:.2px;display:none}
 .artist-hero-fans.show{display:block}
 @media(max-width:768px){
   .artist-hero-bg{filter:brightness(0.75) saturate(0.85);transform:scale(1)}