Path C: legacy CPAL output-sink enumeration was inlined directly in
commands/playback.rs (cfg-gated Linux + non-Linux variants), with
no equivalent in any domain crate. Extract a domain function
`qbz_audio::output_sinks::list_output_sinks` that returns the same
{name, description, volume, is_default} shape (mirrored as the new
public `OutputSinkInfo` struct) for both Linux and non-Linux
platforms, preserving the original logging cadence and the rule
that name == CPAL device name (so saved IDs reopen correctly).
Add v2_get_pipewire_sinks in commands_v2/audio.rs that calls into
qbz_audio directly — no `crate::commands::*` delegation. Updates the
two frontend call sites (AudioOutputBadges.loadStatus and
SettingsView.loadAudioDevices). Legacy command in
commands/playback.rs is preserved untouched; the audio-protected
files (pipewire_backend.rs, audio_settings.rs, player init_device)
are not modified.
cc
vicrodh
c70db4157a