feat(settings): audio output device picker (labels, OS default, live refresh) (#173)

* feat(settings): clearer audio device labels for duplicate ALSA names

Show HDMI outputs as "Card (HDMI n)" from hdmi:DEV indices; include PCM and
optional subdevice for hw/plughw/sysdefault; label other ALSA plugins with
iface and PCM. When labels still collide, append a structured hint
(iface · card · PCM) instead of only truncating the raw device string.

* feat(settings): improve audio output device picker

Parse ALSA-style ids into clearer labels (HDMI with DEV index, PCM/subdevice
for hw/plughw/sysdefault). Disambiguate colliding labels; share stderr
suppression for Linux device enumeration.

Add audio_default_output_device_name and tag the matching list entry as the
current system output (i18n). While the Audio tab is open, refresh list and
mark on audio:device-changed and audio:device-reset without toggling the
refresh spinner. Show an error toast if listing devices fails.

src-tauri/src/lib.rs

@@ -1714,6 +1714,7 @@ pub fn run() {
             audio::audio_set_crossfade,
             audio::audio_set_gapless,
             audio::audio_list_devices,
+            audio::audio_default_output_device_name,
             audio::audio_set_device,
             audio::audio_chain_preload,
             discord::discord_update_presence,