feat(lyrics): configurable sources with drag-to-reorder + feat(audio): ReplayGain pre-gain & fallback

Lyrics Sources:
- Replace lyricsServerFirst + enableNeteaselyrics toggles with a new
  Settings section — three sources (Server, LRCLIB, Netease) each
  individually toggled and drag-reorderable via psy-drop DnD
- useLyrics.ts iterates sources in user-defined order, skipping disabled
  ones; embedded SYLT from local files still wins unconditionally
- onRehydrateStorage migration from legacy fields on first load

ReplayGain Pre-Gain:
- New authStore fields: replayGainPreGainDb (0…+6 dB) and
  replayGainFallbackDb (-6…0 dB, untagged / radio)
- audio.rs compute_gain applies pre_gain_db and fallback_db
- Settings sliders under ReplayGain mode selector
- Radio HTML5 volume scaled by fallbackDb factor on playRadio

i18n(ru): incorporate PR #148 translation improvements (kilyabin)
All 7 locales updated for new keys.

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

src/locales/de.ts

@@ -491,6 +491,11 @@ export const deTranslation = {
     lyricsServerFirstDesc: 'Server-seitige Lyrics (eingebettete Tags, Sidecar-Dateien) vor LRCLIB abfragen. Deaktivieren, um LRCLIB zuerst zu verwenden.',
     enableNeteaselyrics: 'Netease Cloud Music Lyrics',
     enableNeteaselyricsDesc: 'Netease Cloud Music als letzte Lyrics-Quelle verwenden, wenn Server und LRCLIB nichts liefern. Besonders gut für asiatische und internationale Musik.',
+    lyricsSourcesTitle: 'Lyrics-Quellen',
+    lyricsSourcesDesc: 'Wähle, welche Quellen für Lyrics abgefragt werden und in welcher Reihenfolge. Ziehen zum Sortieren. Deaktivierte Quellen werden übersprungen.',
+    lyricsSourceServer: 'Server',
+    lyricsSourceLrclib: 'LRCLIB',
+    lyricsSourceNetease: 'Netease Cloud Music',
     downloadsTitle: 'ZIP-Export & Archivierung',
     downloadsFolderDesc: 'Zielverzeichnis für Alben, die du als ZIP-Datei auf deinen Computer herunterlädst.',
     downloadsDefault: 'Standard-Downloads-Ordner',
@@ -574,6 +579,8 @@ export const deTranslation = {
     replayGainMode: 'Modus',
     replayGainTrack: 'Track',
     replayGainAlbum: 'Album',
+    replayGainPreGain: 'Pre-Gain (getaggte Dateien)',
+    replayGainFallback: 'Fallback (ohne Tags / Radio)',
     crossfade: 'Crossfade',
     crossfadeDesc: 'Überblendung zwischen Tracks',
     crossfadeSecs: '{{n}} s',

src/locales/en.ts

@@ -492,6 +492,11 @@ export const enTranslation = {
     lyricsServerFirstDesc: 'Check server-provided lyrics (embedded tags, sidecar files) before querying LRCLIB. Disable to use LRCLIB first.',
     enableNeteaselyrics: 'Netease Cloud Music lyrics',
     enableNeteaselyricsDesc: 'Use Netease Cloud Music as a last-resort lyrics source when server and LRCLIB both return nothing. Best coverage for Asian and international music.',
+    lyricsSourcesTitle: 'Lyrics Sources',
+    lyricsSourcesDesc: 'Choose which sources to query for lyrics and in what order. Drag to reorder. Disabled sources are skipped entirely.',
+    lyricsSourceServer: 'Server',
+    lyricsSourceLrclib: 'LRCLIB',
+    lyricsSourceNetease: 'Netease Cloud Music',
     downloadsTitle: 'ZIP Export & Archiving',
     downloadsFolderDesc: 'Destination folder for albums you download as a ZIP file to your computer.',
     downloadsDefault: 'Default Downloads Folder',
@@ -575,6 +580,8 @@ export const enTranslation = {
     replayGainMode: 'Mode',
     replayGainTrack: 'Track',
     replayGainAlbum: 'Album',
+    replayGainPreGain: 'Pre-Gain (tagged files)',
+    replayGainFallback: 'Fallback (untagged / radio)',
     crossfade: 'Crossfade',
     crossfadeDesc: 'Fade between tracks',
     crossfadeSecs: '{{n}} s',

src/locales/fr.ts

@@ -489,6 +489,11 @@ export const frTranslation = {
     lyricsServerFirstDesc: 'Consulter d\'abord les paroles fournies par le serveur (tags intégrés, fichiers sidecar) avant LRCLIB. Désactiver pour utiliser LRCLIB en priorité.',
     enableNeteaselyrics: 'Paroles Netease Cloud Music',
     enableNeteaselyricsDesc: 'Utiliser Netease Cloud Music en dernier recours lorsque le serveur et LRCLIB ne retournent rien. Meilleure couverture pour la musique asiatique et internationale.',
+    lyricsSourcesTitle: 'Sources de paroles',
+    lyricsSourcesDesc: 'Choisissez quelles sources interroger et dans quel ordre. Glissez pour réordonner. Les sources désactivées sont ignorées.',
+    lyricsSourceServer: 'Serveur',
+    lyricsSourceLrclib: 'LRCLIB',
+    lyricsSourceNetease: 'Netease Cloud Music',
     downloadsTitle: 'Export ZIP & Archivage',
     downloadsFolderDesc: 'Dossier de destination pour les albums téléchargés en tant que fichier ZIP sur votre ordinateur.',
     downloadsDefault: 'Dossier de téléchargement par défaut',
@@ -572,6 +577,8 @@ export const frTranslation = {
     replayGainMode: 'Mode',
     replayGainTrack: 'Piste',
     replayGainAlbum: 'Album',
+    replayGainPreGain: 'Pré-Gain (fichiers taggés)',
+    replayGainFallback: 'Repli (sans tags / radio)',
     crossfade: 'Fondu enchaîné',
     crossfadeDesc: 'Fondu entre les pistes',
     crossfadeSecs: '{{n}} s',

src/locales/nb.ts

@@ -488,6 +488,11 @@ export const nbTranslation = {
     lyricsServerFirstDesc: 'Sjekk tjenerlevererte sangtekster (innebygde tagger, sidecar-filer) før LRCLIB. Deaktiver for å bruke LRCLIB først.',
     enableNeteaselyrics: 'Netease Cloud Music sangtekster',
     enableNeteaselyricsDesc: 'Bruk Netease Cloud Music som siste utvei når server og LRCLIB ikke finner noe. Best dekning for asiatisk og internasjonal musikk.',
+    lyricsSourcesTitle: 'Sangtekstkilder',
+    lyricsSourcesDesc: 'Velg hvilke kilder som skal brukes og i hvilken rekkefølge. Dra for å sortere. Deaktiverte kilder hoppes over.',
+    lyricsSourceServer: 'Tjener',
+    lyricsSourceLrclib: 'LRCLIB',
+    lyricsSourceNetease: 'Netease Cloud Music',
     downloadsTitle: 'ZIP Eksport & Arkivering',
 	downloadsFolderDesc: 'Målmappe for album du laster ned som en ZIP-fil til datamaskinen din.',												  
     downloadsDefault: 'Standard nedlastingsmappe',
@@ -571,6 +576,8 @@ export const nbTranslation = {
     replayGainMode: 'Modus',
     replayGainTrack: 'Spor',
     replayGainAlbum: 'Album',
+    replayGainPreGain: 'Pre-Gain (taggede filer)',
+    replayGainFallback: 'Reserveverdi (uten tagger / radio)',
     crossfade: 'Crossfade',
     crossfadeDesc: 'Tone mellom spor',
     crossfadeSecs: '{{n}}s',

src/locales/nl.ts

@@ -489,6 +489,11 @@ export const nlTranslation = {
     lyricsServerFirstDesc: 'Controleer eerst door de server geleverde songteksten (ingebedde tags, sidecar-bestanden) vóór LRCLIB. Uitschakelen om LRCLIB eerst te gebruiken.',
     enableNeteaselyrics: 'Netease Cloud Music songteksten',
     enableNeteaselyricsDesc: 'Gebruik Netease Cloud Music als laatste bron wanneer server en LRCLIB niets opleveren. Beste dekking voor Aziatische en internationale muziek.',
+    lyricsSourcesTitle: 'Songtekstbronnen',
+    lyricsSourcesDesc: 'Kies welke bronnen worden geraadpleegd en in welke volgorde. Sleep om te sorteren. Uitgeschakelde bronnen worden overgeslagen.',
+    lyricsSourceServer: 'Server',
+    lyricsSourceLrclib: 'LRCLIB',
+    lyricsSourceNetease: 'Netease Cloud Music',
     downloadsTitle: 'ZIP-export & Archivering',
     downloadsFolderDesc: 'Doelmap voor albums die je als ZIP-bestand naar je computer downloadt.',
     downloadsDefault: 'Standaard downloadmap',
@@ -572,6 +577,8 @@ export const nlTranslation = {
     replayGainMode: 'Modus',
     replayGainTrack: 'Nummer',
     replayGainAlbum: 'Album',
+    replayGainPreGain: 'Pre-Gain (getagde bestanden)',
+    replayGainFallback: 'Terugval (zonder tags / radio)',
     crossfade: 'Overgang',
     crossfadeDesc: 'Fade tussen nummers',
     crossfadeSecs: '{{n}} s',

src/locales/ru.ts

@@ -512,6 +512,11 @@ export const ruTranslation = {
     lyricsServerFirstDesc: 'Проверять тексты песен, предоставленные сервером (встроенные теги, sidecar-файлы) перед запросом LRCLIB. Отключите, чтобы сначала использовать LRCLIB.',
     enableNeteaselyrics: 'Тексты из Netease Cloud Music',
     enableNeteaselyricsDesc: 'Использовать Netease Cloud Music как последний источник текстов, когда остальные способы не находят ничего. Лучшее покрытие для азиатской и международной музыки.',
+    lyricsSourcesTitle: 'Источники текстов',
+    lyricsSourcesDesc: 'Выберите источники для поиска текстов и их порядок. Перетаскивайте для сортировки. Отключённые источники пропускаются.',
+    lyricsSourceServer: 'Сервер',
+    lyricsSourceLrclib: 'LRCLIB',
+    lyricsSourceNetease: 'Netease Cloud Music',
     downloadsTitle: 'Экспорт ZIP и архивов',
     downloadsFolderDesc: 'Куда сохранять альбомы в ZIP архиве на диск.',
     downloadsDefault: 'Папка «Загрузки» по умолчанию',
@@ -600,6 +605,8 @@ export const ruTranslation = {
     replayGainMode: 'Режим',
     replayGainTrack: 'По треку',
     replayGainAlbum: 'По альбому',
+    replayGainPreGain: 'Предусиление (файлы с тегами)',
+    replayGainFallback: 'Резерв (без тегов / радио)',
     crossfade: 'Кроссфейд',
     crossfadeDesc: 'Плавный переход между треками',
     crossfadeSecs: '{{n}} с',

src/locales/zh.ts

@@ -485,6 +485,11 @@ export const zhTranslation = {
     lyricsServerFirstDesc: '先查询服务器提供的歌词（内嵌标签、sidecar 文件），再查询 LRCLIB。禁用则优先使用 LRCLIB。',
     enableNeteaselyrics: '网易云音乐歌词',
     enableNeteaselyricsDesc: '当服务器和 LRCLIB 均无结果时，使用网易云音乐作为最终歌词来源。对亚洲及国际音乐覆盖最佳。',
+    lyricsSourcesTitle: '歌词来源',
+    lyricsSourcesDesc: '选择要查询的歌词来源及其顺序。拖动以排序。已禁用的来源将被跳过。',
+    lyricsSourceServer: '服务器',
+    lyricsSourceLrclib: 'LRCLIB',
+    lyricsSourceNetease: '网易云音乐',
     downloadsTitle: 'ZIP 导出与归档',
     downloadsFolderDesc: '将专辑以 ZIP 文件下载到电脑时的目标文件夹。',
     downloadsDefault: '默认下载文件夹',
@@ -568,6 +573,8 @@ export const zhTranslation = {
     replayGainMode: '模式',
     replayGainTrack: '曲目',
     replayGainAlbum: '专辑',
+    replayGainPreGain: '预增益（有标签文件）',
+    replayGainFallback: '回退增益（无标签 / 收音机）',
     crossfade: '交叉淡入淡出',
     crossfadeDesc: '曲目间淡入淡出',
     crossfadeSecs: '{{n}} 秒',