feat(music): android background playback via media_controls foreground service

Bumps os_media_controls to 4f4b28f3: MediaStyle foreground service with
a JUnit-tested promote/demote/stop policy, artwork URL download (also
fixes video lock-screen art), and task-removal teardown that can't leak
orphan notifications. The music service opts into background mode per
session and requests POST_NOTIFICATIONS before first playback.

pubspec.yaml

@@ -35,7 +35,7 @@ dependencies:
   os_media_controls:
     git:
       url: https://github.com/edde746/media_controls
-      ref: f51c805ebc15bf7a2f49a74174aeb470d3c4c78e
+      ref: 4f4b28f3e669f6ba2421cef5d240ddd37f244b03
   rate_limiter: ^1.0.0
   wakelock_plus:
     git:
@@ -127,7 +127,6 @@ dependency_overrides:
     git:
       url: https://github.com/edde746/material_symbols_icons
       ref: 1d8cd83
-
 sentry:
   org: plezy
   project: plezy