The pinned mpv binary breaks on brew ffmpeg major drift (libavcodec.62 vs
.63 shipped a dead player); making it self-contained costs ~100MB for an
app icon. Removing the whole machinery: build.ts app-bundle assembly,
audio-player bundled-binary resolver + probe (spawns PATH mpv again),
CI mpv install + bundle smoke checks, AppIcon.icns, README note.
Cover-art staging (curl + --cover-art-files) is unrelated and stays.