feat(playlist): add filename sort mode

CLAUDE.md

@@ -97,7 +97,7 @@ Player bar Spotify-style right cluster (Mini-player + Fullscreen primary, Speed/
 
 ### Playlists ([`docs/features/playlists.md`](docs/features/playlists.md), [`docs/features/smart-playlists.md`](docs/features/smart-playlists.md))
 
-Playlist sort dropdown (custom / title / artist / album / recently added / duration — non-custom modes are display-only via `Intl.Collator`, never touch `playlist_track.position`) · auto-cover (Spotify-style 2×2 grid composite from first 4 tracks; manual upload flips `cover_is_auto=0`) · smart playlists (Daily Mix family + recursive boolean rule tree via `CustomRules`, v1 flat → v2 tree auto-migration) · M3U import/export.
+Playlist sort dropdown (custom / title / artist / album / recently added / duration / filename — non-custom modes are display-only via `Intl.Collator`, never touch `playlist_track.position`; filename sorts on the cross-platform basename of `track.file_path`) · auto-cover (Spotify-style 2×2 grid composite from first 4 tracks; manual upload flips `cover_is_auto=0`) · smart playlists (Daily Mix family + recursive boolean rule tree via `CustomRules`, v1 flat → v2 tree auto-migration) · M3U import/export.
 
 ### Integrations ([`docs/features/integrations.md`](docs/features/integrations.md))
 

src/components/views/PlaylistView.tsx

@@ -88,7 +88,8 @@ type PlaylistSortMode =
   | "artist"
   | "album"
   | "added_at"
-  | "duration_ms";
+  | "duration_ms"
+  | "filename";
 
 const PLAYLIST_SORT_MODES: ReadonlyArray<PlaylistSortMode> = [
   "custom",
@@ -97,8 +98,19 @@ const PLAYLIST_SORT_MODES: ReadonlyArray<PlaylistSortMode> = [
   "album",
   "added_at",
   "duration_ms",
+  "filename",
 ];
 
+/** Cross-platform basename — handles both Windows (`\`) and POSIX
+ *  (`/`) separators since profiles can ship libraries scanned on
+ *  either OS, and an imported `.waveflow` archive may cross
+ *  platforms. */
+function basename(path: string): string {
+  const slash = path.lastIndexOf("/");
+  const back = path.lastIndexOf("\\");
+  return path.slice(Math.max(slash, back) + 1);
+}
+
 function isPlaylistSortMode(value: string): value is PlaylistSortMode {
   return (PLAYLIST_SORT_MODES as readonly string[]).includes(value);
 }
@@ -203,6 +215,16 @@ export function PlaylistView({
       case "duration_ms":
         sorted.sort((a, b) => (b.duration_ms ?? 0) - (a.duration_ms ?? 0));
         break;
+      case "filename":
+        // Numeric collator gives a natural order on "1 …", "2 …",
+        // "10 …" filenames — the most common manual-numbering scheme
+        // (matches Explorer / Finder behaviour). Sorted on the basename
+        // only so users grouping by parent folder still see filename
+        // order, not full-path lexicographic order.
+        sorted.sort((a, b) =>
+          collator.compare(basename(a.file_path), basename(b.file_path)),
+        );
+        break;
     }
     return sorted;
   }, [tracks, sortMode]);
@@ -1225,6 +1247,7 @@ function PlaylistSortMenu({ current, onChange, t }: PlaylistSortMenuProps) {
     album: t("sort.album"),
     added_at: t("sort.recentlyAdded", "Recently added"),
     duration_ms: t("sort.duration"),
+    filename: t("sort.filename"),
   };
 
   return (

src/i18n/locales/ar.json

@@ -1036,7 +1036,8 @@
     "albumsCount": "عدد الألبومات",
     "tracksCount": "عدد الأغاني",
     "ascending": "كروسان",
-    "descending": "تنازلي"
+    "descending": "تنازلي",
+    "filename": "اسم الملف"
   },
   "settings": {
     "title": "الإعدادات",

src/i18n/locales/de.json

@@ -1036,7 +1036,8 @@
     "albumsCount": "Anzahl der Alben",
     "tracksCount": "Anzahl der Titel",
     "ascending": "Croissant",
-    "descending": "Absteigend"
+    "descending": "Absteigend",
+    "filename": "Dateiname"
   },
   "settings": {
     "title": "Einstellungen",

src/i18n/locales/en.json

@@ -1048,7 +1048,8 @@
     "albumsCount": "Number of albums",
     "tracksCount": "Number of tracks",
     "ascending": "Croissant",
-    "descending": "Descending"
+    "descending": "Descending",
+    "filename": "Filename"
   },
   "settings": {
     "title": "Settings",

src/i18n/locales/es.json

@@ -1036,7 +1036,8 @@
     "albumsCount": "N.º de álbumes",
     "tracksCount": "N.º de canciones",
     "ascending": "Croissant",
-    "descending": "Descendente"
+    "descending": "Descendente",
+    "filename": "Nombre del archivo"
   },
   "settings": {
     "title": "Configuración",

src/i18n/locales/fr.json

@@ -1048,7 +1048,8 @@
     "albumsCount": "Nb albums",
     "tracksCount": "Nb morceaux",
     "ascending": "Croissant",
-    "descending": "Décroissant"
+    "descending": "Décroissant",
+    "filename": "Nom de fichier"
   },
   "settings": {
     "title": "Paramètres",

src/i18n/locales/hi.json

@@ -1036,7 +1036,8 @@
     "albumsCount": "एल्बमों की संख्या",
     "tracksCount": "ट्रैकों की संख्या",
     "ascending": "क्रोइसाँ",
-    "descending": "उतरता हुआ"
+    "descending": "उतरता हुआ",
+    "filename": "फ़ाइल का नाम"
   },
   "settings": {
     "title": "सेटिंग्स",

src/i18n/locales/id.json

@@ -1036,7 +1036,8 @@
     "albumsCount": "Album",
     "tracksCount": "Lagu",
     "ascending": "Naik",
-    "descending": "Menurun"
+    "descending": "Menurun",
+    "filename": "Nama berkas"
   },
   "settings": {
     "title": "Pengaturan",

src/i18n/locales/it.json

@@ -1036,7 +1036,8 @@
     "albumsCount": "Numero di album",
     "tracksCount": "Numero di brani",
     "ascending": "Croissant",
-    "descending": "Decrescente"
+    "descending": "Decrescente",
+    "filename": "Nome file"
   },
   "settings": {
     "title": "Impostazioni",

src/i18n/locales/ja.json

@@ -1036,7 +1036,8 @@
     "albumsCount": "アルバム数",
     "tracksCount": "曲数",
     "ascending": "クロワッサン",
-    "descending": "降順"
+    "descending": "降順",
+    "filename": "ファイル名"
   },
   "settings": {
     "title": "設定",

src/i18n/locales/kr.json

@@ -1036,7 +1036,8 @@
     "albumsCount": "앨범 수",
     "tracksCount": "곡 수",
     "ascending": "크루아상",
-    "descending": "내림차순"
+    "descending": "내림차순",
+    "filename": "파일 이름"
   },
   "settings": {
     "title": "설정",

src/i18n/locales/nl.json

@@ -1036,7 +1036,8 @@
     "albumsCount": "Aantal albums",
     "tracksCount": "Aantal nummers",
     "ascending": "Croissant",
-    "descending": "Afnemend"
+    "descending": "Afnemend",
+    "filename": "Bestandsnaam"
   },
   "settings": {
     "title": "Instellingen",

src/i18n/locales/pt-BR.json

@@ -1036,7 +1036,8 @@
     "albumsCount": "Número de álbuns",
     "tracksCount": "Número de faixas",
     "ascending": "Croissant",
-    "descending": "Decrescente"
+    "descending": "Decrescente",
+    "filename": "Nome do arquivo"
   },
   "settings": {
     "title": "Configurações",

src/i18n/locales/pt.json

@@ -1036,7 +1036,8 @@
     "albumsCount": "N.º de álbuns",
     "tracksCount": "N.º de faixas",
     "ascending": "Croissant",
-    "descending": "Decrescente"
+    "descending": "Decrescente",
+    "filename": "Nome do ficheiro"
   },
   "settings": {
     "title": "Parâmetros",

src/i18n/locales/ru.json

@@ -1036,7 +1036,8 @@
     "albumsCount": "Альбомы",
     "tracksCount": "Треки",
     "ascending": "По возрастанию",
-    "descending": "По убыванию"
+    "descending": "По убыванию",
+    "filename": "Имя файла"
   },
   "settings": {
     "title": "Настройки",

src/i18n/locales/tr.json

@@ -1036,7 +1036,8 @@
     "albumsCount": "Albümler",
     "tracksCount": "Parçalar",
     "ascending": "Artan",
-    "descending": "Azalan"
+    "descending": "Azalan",
+    "filename": "Dosya adı"
   },
   "settings": {
     "title": "Ayarlar",

src/i18n/locales/zh-CN.json

@@ -1036,7 +1036,8 @@
     "albumsCount": "专辑数量",
     "tracksCount": "曲目数",
     "ascending": "牛角包",
-    "descending": "降序"
+    "descending": "降序",
+    "filename": "文件名"
   },
   "settings": {
     "title": "设置",

src/i18n/locales/zh-TW.json

@@ -1036,7 +1036,8 @@
     "albumsCount": "專輯數量",
     "tracksCount": "曲目數",
     "ascending": "可頌",
-    "descending": "遞減"
+    "descending": "遞減",
+    "filename": "檔案名稱"
   },
   "settings": {
     "title": "設定",