Shippy Alpha R15.3

Critical playback identity hotfix.\n\n- Keeps audio, title, artwork, lyrics, and queue highlight on one committed Media3 item.\n- Synchronizes queue order and current index atomically across shuffle changes.\n- Resolves provider look-ahead in actual shuffled playback order.\n- Retains the R15.2 package ID and signing certificate for an in-place update.\n\nValidation: 15 focused playback/queue/provider tests, formatting check, and debug APK assembly passed. Physical device verification is still required.