The non-mixing playback session was activated in didFinishLaunching,
so merely opening the app stopped other apps' audio. Keep the category
configuration; playback start activates the session.
Audio-only mpv core on every platform (dedicated
com.plezy/mpv_audio_player channels): parameterized android/windows/
linux mpv plugins and a new apple MpvAudioPlayerCore, all skipping
video/window paths (vid=no, audio-display=no, gapless-audio=weak).
MusicPlaybackService drives an in-memory queue with shuffle/repeat,
file-loaded-event gapless arming (property edges coalesce and the
android bridge drops them), per-track progress reporting, OS media
controls, audio focus, sleep timer, and error auto-skip.
PlaybackCoordinator enforces one live native player: starting video
disposes the audio core first.
Re-enables Audio Passthrough on Apple TV against the MPVKit EAC3-JOC
AVPlayer sink (pin bump to v1.0.8 follows), adds an AVPlayer test
harness + diagnostics screen for #1300, and makes loudnorm yield while
passthrough is active (fixes a latent spdif conflict on desktop too).
edde746