On macOS 27 beta, CoreAudio rejects ao_coreaudio's channel-layout setup
with paramErr (-50), and since 2.14.0 pinned ao=coreaudio as the only
output, the failed init left every video playing with no audio and no
selectable audio track. Append avfoundation as the fallback, mirroring
upstream mpv's macOS probe order: every format still opens through the
HAL-backed CoreAudio path when it works, and the fallback only engages
when CoreAudio's init fails outright.
close#1964
The AVFoundation/CoreAudio split still left PCM on AVFoundation and maintained two macOS timing paths. Select CoreAudio as the sole macOS audio output so PCM and compressed streams share the HAL-backed implementation. This intentionally drops macOS AVFoundation spatialization; iOS and tvOS remain unchanged.
AC3/EAC3 playback could stutter after AVFoundation began handling compressed streams. Decline compressed formats in macOS AVFoundation so mpv falls through to CoreAudio, while retaining AVFoundation for PCM and the tvOS Dolby path.
close#1940