feat(android): global 30s-preview control bar + artist fan count

Preview bar:
- 30s previews used to keep playing with no control once you left the album/artist/Explore
  screen they started on. Moved the preview player from ExploreViewModel to an app-level
  PreviewController, and added a global PreviewBar (above the mini player, on every screen)
  to pause/resume/stop it. Starting real library playback cancels the preview.

Artist fan count (parity with web):
- ItunesItem carries fanCount (Deezer nb_fan); shown on search artist cards and the artist
  page ("559.542 Fans" / "1,2 Mio. Fans"). Combined with the existing nb_fan sort this makes
  same-name collisions (5x "Joji") resolve to the right artist on Android too.

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

CHANGELOG.md

@@ -26,6 +26,9 @@ Versioning: two-part `MAJOR.MINOR` — each release bumps the minor (features an
 | Artist page (Navidrome)          | ✅        | ✅      |
 | Artist page (Deezer fallback)    | ✅        | ✅      |
 | Global search source             | Deezer    | Deezer  |
+| Same-name artist disambiguation  | ✅        | ✅      |
+| Artist fan count shown           | ✅        | ✅      |
+| 30s preview control bar          | ✅        | ✅      |
 | Concert events (Ticketmaster)    | ✅        | ✅      |
 | Genre browsing                   | ✅        | ✅      |
 | Global search                    | ✅        | ✅      |
@@ -71,10 +74,12 @@ Big change: **the entire metadata/search stack moved from Apple's iTunes to Deez
 - **Backend** — Removed the dead iTunes `/search` proxy and the Apple charts RSS proxy; the Deezer proxy (`/api/deezer/*`) now also serves charts and the editor lookup
 
 ### Added
+- **Web + Android** — **Same-name artist disambiguation**: Deezer's artist search isn't ranked by popularity, so a name collision (5 artists named "Joji") returned a niche one first — the artist page then loaded the wrong discography and owned songs didn't show as downloaded. Artists are now sorted by Deezer fan count, and on a local artist page with a real collision the pick is tie-broken by **song overlap** with your library (each artist has different songs). The **fan count is shown** on search artist cards and the artist page
+- **Android** — **Global 30s-preview control bar**: a preview started on an album/artist/Explore screen used to keep playing with no way to stop it once you navigated away. The preview now lives at the app level with a bar (above the mini player, on every screen) to pause/resume/stop it; starting real playback cancels the preview
 - **Backend** — Unit tests for the Deezer mapping/matching logic (`backend/test/deezer.test.js`, run with `npm test`), incl. per-track numbering, mixed-artist album-artist stability, explicit flags and the Japanese-title match guard. A live smoke test runs with `RUN_LIVE=1`
 
 ### Notes
-- Deploy: `git pull`, then rebuild the frontend (`docker compose up -d --build novasonic-frontend`) and restart the backend (`docker compose restart novasonic-backend`). Service worker bumped to `ns-v51`
+- Deploy: `git pull`, then rebuild the frontend (`docker compose up -d --build novasonic-frontend`) and restart the backend (`docker compose restart novasonic-backend`). Service worker bumped to `ns-v53`
 - Titles a user picked stay as chosen; only derived fields (album, album-artist, genre, year, artwork) follow Deezer
 
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