feat(tracks): add Tracks library hub page (closes #299) (#300)

New /tracks route with three sections:

- Hero "Track of the moment" — random pick with play / enqueue / reroll
- Random Pick rail — 18 song cards, rerollable; hero song deduped
- Browse all tracks — virtualized list (@tanstack/react-virtual),
  paginated 50 at a time

Browse uses Navidrome's native /api/song?_sort=title&_order=ASC for
proper A-Z order (no Subsonic equivalent), with automatic fallback
to search3 on non-Navidrome servers. Search input drives search3
with 300ms debounce. Bearer token cached module-level, re-auth on 401.

Play button on rows + cards calls a new enqueueAndPlay() helper that
appends to the existing queue (skip if duplicate) and jumps to the
song — different from playSongNow which replaces the queue. Enqueue
button stays opaque (no hover-only).

i18n keys for sidebar.tracks + tracks.* namespace in all 8 locales.
New AudioLines sidebar icon. Sidebar entry inserted between
"All Albums" and "Build a Mix".

Performance: cover thumbnails dropped (uniform layout instead),
RAF-throttled scroll prefetch, hover transforms removed from cards
(WebKitGTK compositing-friendly).

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/locales/de.ts

@@ -21,6 +21,7 @@ export const deTranslation = {
     cancelDownload: 'Download abbrechen',
     offlineLibrary: 'Offline-Bibliothek',
     genres: 'Genres',
+    tracks: 'Titel',
     playlists: 'Playlists',
     mostPlayed: 'Meistgehört',
     radio: 'Internetradio',
@@ -377,6 +378,20 @@ export const deTranslation = {
     offlineQueuing: '{{count}} Album(s) für Offline einreihen…',
     offlineFailed: '{{name}} konnte nicht offline hinzugefügt werden',
   },
+  tracks: {
+    title: 'Titel',
+    subtitle: 'Stöbern. Suchen. Entdecken.',
+    heroEyebrow: 'Titel des Moments',
+    heroReroll: 'Anderen wählen',
+    playSong: 'Abspielen',
+    enqueueSong: 'Zur Warteschlange',
+    railRandom: 'Zufallsauswahl',
+    browseTitle: 'Alle Titel durchstöbern',
+    browseUnsupported: 'Dieser Server listet nicht die ganze Bibliothek auf einmal. Nutze die Suche oben, um bestimmte Titel zu finden.',
+    searchPlaceholder: 'Titel, Künstler oder Album suchen…',
+    count_one: '{{count}} Titel',
+    count_other: '{{count}} Titel',
+  },
   artists: {
     title: 'Künstler',
     search: 'Suchen…',

src/locales/en.ts

@@ -22,6 +22,7 @@ export const enTranslation = {
     cancelDownload: 'Cancel download',
     offlineLibrary: 'Offline Library',
     genres: 'Genres',
+    tracks: 'Tracks',
     playlists: 'Playlists',
     smartPlaylists: 'Smart Playlists',
     mostPlayed: 'Most Played',
@@ -379,6 +380,20 @@ export const enTranslation = {
     offlineQueuing: 'Queuing {{count}} album(s) for offline…',
     offlineFailed: 'Failed to add {{name}} offline',
   },
+  tracks: {
+    title: 'Tracks',
+    subtitle: 'Browse. Search. Discover.',
+    heroEyebrow: 'Track of the moment',
+    heroReroll: 'Pick another',
+    playSong: 'Play',
+    enqueueSong: 'Add to queue',
+    railRandom: 'Random Pick',
+    browseTitle: 'Browse all tracks',
+    browseUnsupported: "This server doesn't list the whole library at once. Use the search above to find specific tracks.",
+    searchPlaceholder: 'Find a track by title, artist or album…',
+    count_one: '{{count}} track',
+    count_other: '{{count}} tracks',
+  },
   artists: {
     title: 'Artists',
     search: 'Search…',

src/locales/es.ts

@@ -22,6 +22,7 @@ export const esTranslation = {
     cancelDownload: 'Cancelar descarga',
     offlineLibrary: 'Biblioteca Offline',
     genres: 'Géneros',
+    tracks: 'Canciones',
     playlists: 'Listas de Reproducción',
     mostPlayed: 'Más Reproducidos',
     radio: 'Radio por Internet',
@@ -379,6 +380,20 @@ export const esTranslation = {
     offlineFailed: 'Error al agregar {{name}} offline',
     addToPlaylist: 'Agregar a Lista de Reproducción',
   },
+  tracks: {
+    title: 'Canciones',
+    subtitle: 'Explorar. Buscar. Descubrir.',
+    heroEyebrow: 'Canción del momento',
+    heroReroll: 'Elegir otra',
+    playSong: 'Reproducir',
+    enqueueSong: 'Añadir a la cola',
+    railRandom: 'Selección aleatoria',
+    browseTitle: 'Explorar todas las canciones',
+    browseUnsupported: 'Este servidor no lista toda la biblioteca de una vez. Usa la búsqueda de arriba para encontrar canciones concretas.',
+    searchPlaceholder: 'Busca una canción por título, artista o álbum…',
+    count_one: '{{count}} canción',
+    count_other: '{{count}} canciones',
+  },
   artists: {
     title: 'Artistas',
     search: 'Buscar…',

src/locales/fr.ts

@@ -21,6 +21,7 @@ export const frTranslation = {
     cancelDownload: 'Annuler le téléchargement',
     offlineLibrary: 'Bibliothèque hors ligne',
     genres: 'Genres',
+    tracks: 'Titres',
     playlists: 'Playlists',
     mostPlayed: 'Les plus joués',
     radio: 'Radio Internet',
@@ -377,6 +378,20 @@ export const frTranslation = {
     offlineQueuing: 'Mise en file d\'attente de {{count}} album(s) hors ligne…',
     offlineFailed: 'Échec de l\'ajout de {{name}} hors ligne',
   },
+  tracks: {
+    title: 'Titres',
+    subtitle: 'Parcourir. Chercher. Découvrir.',
+    heroEyebrow: 'Titre du moment',
+    heroReroll: 'En choisir un autre',
+    playSong: 'Lire',
+    enqueueSong: 'Ajouter à la file',
+    railRandom: 'Sélection aléatoire',
+    browseTitle: 'Parcourir tous les titres',
+    browseUnsupported: 'Ce serveur ne liste pas toute la bibliothèque d\'un coup. Utilisez la recherche ci-dessus pour trouver des titres précis.',
+    searchPlaceholder: 'Chercher un titre par titre, artiste ou album…',
+    count_one: '{{count}} titre',
+    count_other: '{{count}} titres',
+  },
   artists: {
     title: 'Artistes',
     search: 'Rechercher…',

src/locales/nb.ts

@@ -21,6 +21,7 @@ export const nbTranslation = {
     cancelDownload: 'Avbryt nedlasting',
     offlineLibrary: 'Frakoblet bibliotek',
     genres: 'Sjangere',
+    tracks: 'Spor',
     playlists: 'Spillelister',
     mostPlayed: 'Mest spilt',
     radio: 'Internettradio',
@@ -377,6 +378,20 @@ export const nbTranslation = {
     offlineQueuing: 'Legger {{count}} album i kø for offline…',
     offlineFailed: 'Kunne ikke legge til {{name}} offline',
   },
+  tracks: {
+    title: 'Spor',
+    subtitle: 'Bla. Søk. Oppdag.',
+    heroEyebrow: 'Sporet akkurat nå',
+    heroReroll: 'Velg et annet',
+    playSong: 'Spill av',
+    enqueueSong: 'Legg til i kø',
+    railRandom: 'Tilfeldig valg',
+    browseTitle: 'Bla gjennom alle spor',
+    browseUnsupported: 'Denne tjeneren lister ikke hele biblioteket på én gang. Bruk søket ovenfor for å finne bestemte spor.',
+    searchPlaceholder: 'Finn et spor etter tittel, artist eller album…',
+    count_one: '{{count}} spor',
+    count_other: '{{count}} spor',
+  },
   artists: {
     title: 'Artister',
     search: 'Søk…',

src/locales/nl.ts

@@ -21,6 +21,7 @@ export const nlTranslation = {
     cancelDownload: 'Download annuleren',
     offlineLibrary: 'Offline bibliotheek',
     genres: 'Genres',
+    tracks: 'Nummers',
     playlists: 'Playlists',
     mostPlayed: 'Meest gespeeld',
     radio: 'Internetradio',
@@ -376,6 +377,20 @@ export const nlTranslation = {
     offlineQueuing: '{{count}} album(s) in wachtrij voor offline…',
     offlineFailed: 'Toevoegen van {{name}} offline mislukt',
   },
+  tracks: {
+    title: 'Nummers',
+    subtitle: 'Bladeren. Zoeken. Ontdekken.',
+    heroEyebrow: 'Nummer van het moment',
+    heroReroll: 'Een ander kiezen',
+    playSong: 'Afspelen',
+    enqueueSong: 'Aan wachtrij toevoegen',
+    railRandom: 'Willekeurige selectie',
+    browseTitle: 'Alle nummers doorbladeren',
+    browseUnsupported: 'Deze server toont niet de hele bibliotheek in één keer. Gebruik de zoekbalk hierboven om specifieke nummers te vinden.',
+    searchPlaceholder: 'Zoek op titel, artiest of album…',
+    count_one: '{{count}} nummer',
+    count_other: '{{count}} nummers',
+  },
   artists: {
     title: 'Artiesten',
     search: 'Zoeken…',

src/locales/ru.ts

@@ -22,6 +22,7 @@ export const ruTranslation = {
     cancelDownload: 'Отменить загрузку',
     offlineLibrary: 'Офлайн-библиотека',
     genres: 'Жанры',
+    tracks: 'Треки',
     playlists: 'Плейлисты',
     smartPlaylists: 'Смарт-плейлисты',
     mostPlayed: 'Популярное',
@@ -401,6 +402,22 @@ export const ruTranslation = {
     offlineQueuing: 'Добавление {{count}} альбом(ов) в офлайн…',
     offlineFailed: 'Не удалось добавить {{name}} офлайн',
   },
+  tracks: {
+    title: 'Треки',
+    subtitle: 'Листать. Искать. Открывать.',
+    heroEyebrow: 'Трек момента',
+    heroReroll: 'Выбрать другой',
+    playSong: 'Воспроизвести',
+    enqueueSong: 'В очередь',
+    railRandom: 'Случайная подборка',
+    browseTitle: 'Просмотреть все треки',
+    browseUnsupported: 'Этот сервер не возвращает всю библиотеку сразу. Воспользуйтесь поиском выше, чтобы найти конкретные треки.',
+    searchPlaceholder: 'Найти трек по названию, исполнителю или альбому…',
+    count_one: '{{count}} трек',
+    count_few: '{{count}} трека',
+    count_many: '{{count}} треков',
+    count_other: '{{count}} треков',
+  },
   artists: {
     title: 'Исполнители',
     search: 'Поиск…',

src/locales/zh.ts

@@ -21,6 +21,7 @@ export const zhTranslation = {
     cancelDownload: '取消下载',
     offlineLibrary: '离线音乐库',
     genres: '流派',
+    tracks: '曲目',
     playlists: '播放列表',
     mostPlayed: '最常播放',
     radio: '网络电台',
@@ -375,6 +376,20 @@ export const zhTranslation = {
     offlineQueuing: '正在将 {{count}} 张专辑加入离线队列…',
     offlineFailed: '添加 {{name}} 离线失败',
   },
+  tracks: {
+    title: '曲目',
+    subtitle: '浏览。搜索。发现。',
+    heroEyebrow: '此刻精选',
+    heroReroll: '换一首',
+    playSong: '播放',
+    enqueueSong: '加入队列',
+    railRandom: '随机精选',
+    browseTitle: '浏览所有曲目',
+    browseUnsupported: '此服务器不支持一次性列出整个音乐库。使用上方的搜索来查找特定曲目。',
+    searchPlaceholder: '按标题、艺人或专辑搜索…',
+    count_one: '{{count}} 首曲目',
+    count_other: '{{count}} 首曲目',
+  },
   artists: {
     title: '艺术家',
     search: '搜索…',