feat(audio): audio output device selection (closes #169)

Adds the ability to choose which audio output device Psysonic plays
through — useful for USB DACs, dedicated soundcards, and multi-device setups.

Rust (audio.rs):
- open_stream_for_device_and_rate(device_name, rate): opens a named
  device by cpal name, falls back to system default if not found
- AudioEngine.selected_device: persists the chosen device across
  stream reopens so hi-res rate switches stay on the right device
- audio_list_devices: Tauri command — returns all output device names
- audio_set_device: Tauri command — switches device immediately,
  drops old sinks, emits audio:device-changed
- start_device_watcher: now handles two cases:
    1. No pinned device + system default changed → reopen on new default
    2. Pinned device disappeared (DAC unplugged) → clear selected_device,
       fall back to system default, emit audio:device-reset

Frontend:
- authStore: audioOutputDevice (string | null), persisted
- playerStore: applies stored device on cold start
- App.tsx: listens to audio:device-reset, clears authStore device
  and restarts playback on the fallback device
- Settings → Audio tab: device dropdown at top (above Hi-Res and EQ),
  uses CustomSelect (portal-based, styled), all 8 locales
- CustomSelect: added disabled prop

Note: exclusive mode (WASAPI exclusive, CoreAudio exclusive) is out
of scope for now.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/locales/de.ts

@@ -499,6 +499,9 @@ export const deTranslation = {
     hotCacheDebounceImmediate: 'Sofort',
     hotCacheDebounceSeconds: '{{n}} s',
     hotCacheClearBtn: 'Hot-Cache leeren',
+    audioOutputDevice: 'Audio-Ausgabegerät',
+    audioOutputDeviceDesc: 'Wähle das Audiogerät, über das Psysonic spielt. Änderungen werden sofort übernommen und starten den aktuellen Track neu.',
+    audioOutputDeviceDefault: 'Systemstandard',
     hiResTitle: 'Native Hi-Res-Wiedergabe',
     hiResEnabled: 'Native Hi-Res-Wiedergabe aktivieren',
     hiResDesc: "Standardmäßig wird auf 44,1 kHz begrenzt (maximale Stabilität). Nur aktivieren, wenn Hardware und Netzwerk zuverlässig hohe Abtastraten (88,2 kHz+) unterstützen.",

src/locales/en.ts

@@ -501,6 +501,9 @@ export const enTranslation = {
     hotCacheDebounceImmediate: 'Immediate',
     hotCacheDebounceSeconds: '{{n}} s',
     hotCacheClearBtn: 'Clear hot cache',
+    audioOutputDevice: 'Audio Output Device',
+    audioOutputDeviceDesc: 'Select which audio device Psysonic plays through. Changes take effect immediately and restart the current track.',
+    audioOutputDeviceDefault: 'System Default',
     hiResTitle: 'Native Hi-Res Playback',
     hiResEnabled: 'Enable native hi-res playback',
     hiResDesc: "Forces 44.1 kHz output by default for maximum stability. Enable only if your hardware and network reliably support high sample rates (88.2 kHz+).",

src/locales/es.ts

@@ -502,6 +502,9 @@ export const esTranslation = {
     hotCacheDebounceImmediate: 'Inmediato',
     hotCacheDebounceSeconds: '{{n}} s',
     hotCacheClearBtn: 'Limpiar caché activa',
+    audioOutputDevice: 'Dispositivo de salida de audio',
+    audioOutputDeviceDesc: 'Selecciona el dispositivo de audio que usa Psysonic. Los cambios surten efecto de inmediato y reinician la pista actual.',
+    audioOutputDeviceDefault: 'Predeterminado del sistema',
     hiResTitle: 'Reproducción Nativa Hi-Res',
     hiResEnabled: 'Habilitar reproducción nativa hi-res',
     hiResDesc: "Fuerza 44.1 kHz de salida por defecto para máxima estabilidad. Habilita solo si tu hardware y red soportan confiablemente altas tasas de muestreo (88.2 kHz+).",

src/locales/fr.ts

@@ -499,6 +499,9 @@ export const frTranslation = {
     hotCacheDebounceImmediate: 'Immédiat',
     hotCacheDebounceSeconds: '{{n}} s',
     hotCacheClearBtn: 'Vider le cache à chaud',
+    audioOutputDevice: 'Périphérique de sortie audio',
+    audioOutputDeviceDesc: 'Choisissez le périphérique audio utilisé par Psysonic. Les changements sont immédiats et relancent la piste en cours.',
+    audioOutputDeviceDefault: 'Défaut système',
     hiResTitle: 'Lecture haute résolution native',
     hiResEnabled: 'Activer la lecture haute résolution native',
     hiResDesc: "Force une sortie à 44,1 kHz par défaut pour une stabilité maximale. N'activer que si le matériel et le réseau prennent en charge les hautes fréquences d'échantillonnage (88,2 kHz+).",

src/locales/nb.ts

@@ -500,6 +500,9 @@ export const nbTranslation = {
     hotCacheDebounceImmediate: 'Umiddelbart',
     hotCacheDebounceSeconds: '{{n}} sek',
     hotCacheClearBtn: 'Tøm varm buffer',
+    audioOutputDevice: 'Lydutgangsenhet',
+    audioOutputDeviceDesc: 'Velg hvilken lydenhet Psysonic spiller gjennom. Endringer trer i kraft umiddelbart og starter gjeldende spor på nytt.',
+    audioOutputDeviceDefault: 'Systemstandard',
     hiResTitle: 'Innebygd hi-res-avspilling',
     hiResEnabled: 'Aktiver innebygd hi-res-avspilling',
     hiResDesc: "Begrenser utdata til 44,1 kHz som standard for maksimal stabilitet. Aktiver kun hvis maskinvare og nettverk støtter høye samplingsrater (88,2 kHz+) pålitelig.",

src/locales/nl.ts

@@ -498,6 +498,9 @@ export const nlTranslation = {
     hotCacheDebounceImmediate: 'Direct',
     hotCacheDebounceSeconds: '{{n}} s',
     hotCacheClearBtn: 'Warme cache wissen',
+    audioOutputDevice: 'Audio-uitvoerapparaat',
+    audioOutputDeviceDesc: 'Kies via welk audioapparaat Psysonic afspeelt. Wijzigingen worden direct toegepast en starten het huidige nummer opnieuw.',
+    audioOutputDeviceDefault: 'Systeemstandaard',
     hiResTitle: 'Natieve hi-res-weergave',
     hiResEnabled: 'Natieve hi-res-weergave inschakelen',
     hiResDesc: "Beperkt de uitvoer standaard tot 44,1 kHz voor maximale stabiliteit. Alleen inschakelen als hardware en netwerk hoge samplerates (88,2 kHz+) ondersteunen.",

src/locales/ru.ts

@@ -516,6 +516,9 @@ export const ruTranslation = {
     hotCacheDebounceImmediate: 'Сразу',
     hotCacheDebounceSeconds: '{{n}} с',
     hotCacheClearBtn: 'Очистить горячий кэш',
+    audioOutputDevice: 'Устройство вывода звука',
+    audioOutputDeviceDesc: 'Выберите аудиоустройство для воспроизведения. Изменения применяются немедленно и перезапускают текущий трек.',
+    audioOutputDeviceDefault: 'Системное по умолчанию',
     hiResTitle: 'Нативное воспроизведение Hi-Res',
     hiResEnabled: 'Включить нативное Hi-Res воспроизведение',
     hiResDesc: "По умолчанию вывод ограничен до 44,1 кГц для максимальной стабильности. Включайте только если оборудование и сеть надёжно поддерживают высокие частоты (88,2 кГц+).",

src/locales/zh.ts

@@ -494,6 +494,9 @@ export const zhTranslation = {
     hotCacheDebounceImmediate: '立即',
     hotCacheDebounceSeconds: '{{n}} 秒',
     hotCacheClearBtn: '清空热缓存',
+    audioOutputDevice: '音频输出设备',
+    audioOutputDeviceDesc: '选择 Psysonic 播放音频的设备。更改立即生效并重新开始当前曲目。',
+    audioOutputDeviceDefault: '系统默认',
     hiResTitle: '原生高清晰度播放',
     hiResEnabled: '启用原生高清晰度播放',
     hiResDesc: "默认强制 44.1 kHz 输出以获得最大稳定性。仅在硬件和网络可靠支持高采样率（88.2 kHz+）时启用。",