feat: scrobbling, genre grid redesign with detail view + play button

- Scrobble to Navidrome on auto-advance (Android) and track end (web)
  so type=recent and type=frequent are accurate for the hero card
- Genre section: pill chips → grid cards with colored left bars
- Top 15 genres shown by default (sorted by song count), expand toggle
- Genre card: click → genre detail page with full song list
- Genre card: hover play button → shuffle-play without navigating
- Genre detail page reuses album-detail layout (back btn, stats, song list)

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

src/main.js

@@ -16,7 +16,7 @@ import {
   onGlobalSearch, s_goArtist, s_goAlbum, playerBarGoArtist, playerBarGoAlbum,
   searchSimilarArtist, searchAndPreview, loadItunesAlbum, expandArtistBio,
   loadAlbums, loadStarred, loadRandom, filterStarred, filterPlaylist,
-  plReorderEnter, plReorderSave, plReorderCancel,
+  plReorderEnter, plReorderSave, plReorderCancel, toggleAllGenres,
 } from './views.js';
 import { loadSpotifyImporter, resolveSpotifyLink, clearSpotifyPreview, spotifyDlAll } from './spotify.js';
 import {
@@ -304,7 +304,7 @@ Object.assign(window, {
   openSidebar, closeSidebar, switchNavMode, showCtxMenu,
   // Views
   loadAlbums, loadStarred, loadRandom, filterStarred, filterPlaylist,
-  plReorderEnter, plReorderSave, plReorderCancel,
+  plReorderEnter, plReorderSave, plReorderCancel, toggleAllGenres,
   loadSpotifyImporter, resolveSpotifyLink, clearSpotifyPreview, spotifyDlAll,
   executeSpotifyDownload,
   openPlModal, closePlModal, addSongsToPlaylist, createAndAddPlaylist, createPlaylistPrompt,