fix(audio): Linux output device selection and watcher (#176)

* fix(audio): stabilize Linux output device picker and watcher

Keep pinned ALSA/cpal device ids stable when enumeration omits the active
sink or returns an equivalent name. Stop Linux device-watcher from clearing
the pin based on missing list entries; macOS and Windows still treat repeated
absence as unplugged. Settings refresh flow calls canonicalize and refetches
the list; add i18n for the out-of-list device label.

* fix(settings): sort audio output devices by label

cpal enumeration order is arbitrary; order the dropdown by readable label
and place the current OS default device first among concrete outputs.

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_canonicalize_selected_device,
             audio::audio_default_output_device_name,
             audio::audio_set_device,
             audio::audio_chain_preload,