feat: v1.30.0 — Discord RPC, offline bulk download, artist images, lazy loading, crossfade fix

- Discord Rich Presence (opt-in) — requested by @Bewenben (#49)
- Bulk offline download for playlists and artist discographies — requested by @Apollosport (#54)
- Offline Library filter tabs: All / Albums / Playlists / Discographies with artist grouping
- Artist images on Artists overview (opt-in, off by default) — reported by @Apollosport (#53)
- Image lazy loading via IntersectionObserver (300px margin) across all pages
- Fix: crossfade no longer triggers on manual track skip — reported by @netherguy4 (#35)
- Fix: playlist offline cache now stored as single entry (not per-album)
- Fix: image cache AbortController no longer blocks IDB writes
- Update toast: experimental auto-update hint + GH download link always visible (Win/Mac)
- Queue tech strip: genre removed
- Facebook theme: contrast, opaque badge/back button, queue tab labels
- "Save discography offline" label (was "Download discography")
- Fix: clearing empty playlists via updatePlaylist.view (Axios empty array workaround)
- starredOverrides propagated to AlbumDetail, Favorites, RandomMix

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

src/pages/OfflineLibrary.tsx

@@ -1,4 +1,4 @@
-import React from 'react';
+import React, { useState } from 'react';
 import { Play, HardDriveDownload, Trash2 } from 'lucide-react';
 import { useTranslation } from 'react-i18next';
 import { useOfflineStore } from '../store/offlineStore';
@@ -7,6 +7,8 @@ import { usePlayerStore } from '../store/playerStore';
 import { buildCoverArtUrl, coverArtCacheKey } from '../api/subsonic';
 import CachedImage from '../components/CachedImage';
 
+type FilterType = 'all' | 'album' | 'playlist' | 'artist';
+
 export default function OfflineLibrary() {
   const { t } = useTranslation();
   const serverId = useAuthStore(s => s.activeServerId ?? '');
@@ -15,26 +17,36 @@ export default function OfflineLibrary() {
   const deleteAlbum = useOfflineStore(s => s.deleteAlbum);
   const playTrack = usePlayerStore(s => s.playTrack);
   const enqueue = usePlayerStore(s => s.enqueue);
+  const [filter, setFilter] = useState<FilterType>('all');
 
   const albums = Object.values(offlineAlbums).filter(a => a.serverId === serverId);
 
-const buildTracks = (albumId: string) => {
-     const meta = offlineAlbums[`${serverId}:${albumId}`];
-     if (!meta) return [];
-     return meta.trackIds.flatMap(tid => {
-       const t = offlineTracks[`${serverId}:${tid}`];
-       if (!t) return [];
-       return [{
-         id: t.id, title: t.title, artist: t.artist, album: t.album,
-         albumId: t.albumId, artistId: t.artistId, duration: t.duration,
-         coverArt: t.coverArt, track: undefined, year: t.year,
-         bitRate: t.bitRate, suffix: t.suffix, genre: t.genre,
-         replayGainTrackDb: t.replayGainTrackDb,
-         replayGainAlbumDb: t.replayGainAlbumDb,
-         replayGainPeak: t.replayGainPeak,
-       }];
-     });
-   };
+  const countByType = (type: FilterType) => {
+    if (type === 'all') return albums.length;
+    return albums.filter(a => (a.type ?? 'album') === type).length;
+  };
+
+  const filtered = filter === 'all'
+    ? albums
+    : albums.filter(a => (a.type ?? 'album') === filter);
+
+  const buildTracks = (albumId: string) => {
+    const meta = offlineAlbums[`${serverId}:${albumId}`];
+    if (!meta) return [];
+    return meta.trackIds.flatMap(tid => {
+      const t = offlineTracks[`${serverId}:${tid}`];
+      if (!t) return [];
+      return [{
+        id: t.id, title: t.title, artist: t.artist, album: t.album,
+        albumId: t.albumId, artistId: t.artistId, duration: t.duration,
+        coverArt: t.coverArt, track: undefined, year: t.year,
+        bitRate: t.bitRate, suffix: t.suffix, genre: t.genre,
+        replayGainTrackDb: t.replayGainTrackDb,
+        replayGainAlbumDb: t.replayGainAlbumDb,
+        replayGainPeak: t.replayGainPeak,
+      }];
+    });
+  };
 
   const handlePlay = (albumId: string) => {
     const tracks = buildTracks(albumId);
@@ -45,6 +57,84 @@ const buildTracks = (albumId: string) => {
     enqueue(buildTracks(albumId));
   };
 
+  const renderCard = (album: typeof albums[0]) => {
+    const coverUrl = album.coverArt ? buildCoverArtUrl(album.coverArt, 300) : '';
+    const cacheKey = album.coverArt ? coverArtCacheKey(album.coverArt, 300) : '';
+    const trackCount = album.trackIds.filter(tid => !!offlineTracks[`${serverId}:${tid}`]).length;
+    return (
+      <div key={`${album.serverId}:${album.id}`} className="album-card card offline-library-card">
+        <div className="album-card-cover">
+          {coverUrl ? (
+            <CachedImage src={coverUrl} cacheKey={cacheKey} alt={`${album.name} Cover`} loading="lazy" />
+          ) : (
+            <div className="album-card-cover-placeholder">
+              <HardDriveDownload size={32} />
+            </div>
+          )}
+          <div className="album-card-play-overlay">
+            <button
+              className="album-card-details-btn"
+              onClick={() => handlePlay(album.id)}
+              aria-label={`${album.name} abspielen`}
+            >
+              <Play size={15} fill="currentColor" />
+            </button>
+          </div>
+        </div>
+        <div className="album-card-info">
+          <p className="album-card-title truncate">{album.name}</p>
+          <p className="album-card-artist truncate">{album.artist}</p>
+          {album.year && <p className="album-card-year">{album.year}</p>}
+          <div className="offline-library-card-meta">
+            <button
+              className="offline-library-enqueue"
+              onClick={() => handleEnqueue(album.id)}
+              data-tooltip={t('queue.addToQueue')}
+              data-tooltip-pos="top"
+            >
+              + Queue
+            </button>
+            <span className="offline-library-tracks">{trackCount} tracks</span>
+            <button
+              className="offline-library-delete"
+              onClick={() => deleteAlbum(album.id, serverId)}
+              data-tooltip={t('albumDetail.removeOffline')}
+              data-tooltip-pos="top"
+            >
+              <Trash2 size={11} />
+            </button>
+          </div>
+        </div>
+      </div>
+    );
+  };
+
+  // For artist filter: group by artist name
+  const renderArtistGroups = () => {
+    const groups: Record<string, typeof albums> = {};
+    for (const album of filtered) {
+      const key = album.artist || '—';
+      if (!groups[key]) groups[key] = [];
+      groups[key].push(album);
+    }
+    const sortedArtists = Object.keys(groups).sort((a, b) => a.localeCompare(b));
+    return sortedArtists.map(artistName => (
+      <div key={artistName} className="offline-artist-group">
+        <h2 className="offline-artist-group-heading">{artistName}</h2>
+        <div className="album-grid-wrap">
+          {groups[artistName].map(renderCard)}
+        </div>
+      </div>
+    ));
+  };
+
+  const TABS: { id: FilterType; labelKey: string }[] = [
+    { id: 'all',      labelKey: 'connection.offlineFilterAll' },
+    { id: 'album',    labelKey: 'connection.offlineFilterAlbums' },
+    { id: 'playlist', labelKey: 'connection.offlineFilterPlaylists' },
+    { id: 'artist',   labelKey: 'connection.offlineFilterArtists' },
+  ];
+
   return (
     <div className="offline-library animate-fade-in">
       <div className="offline-library-header">
@@ -57,60 +147,30 @@ const buildTracks = (albumId: string) => {
         </div>
       </div>
 
-      {albums.length === 0 ? (
+      <div className="offline-filter-tabs">
+        {TABS.map(tab => {
+          const count = countByType(tab.id);
+          if (tab.id !== 'all' && count === 0) return null;
+          return (
+            <button
+              key={tab.id}
+              className={`offline-filter-tab${filter === tab.id ? ' active' : ''}`}
+              onClick={() => setFilter(tab.id)}
+            >
+              {t(tab.labelKey)}
+              <span className="offline-filter-tab-count">{count}</span>
+            </button>
+          );
+        })}
+      </div>
+
+      {filtered.length === 0 ? (
         <div className="empty-state">{t('connection.offlineLibraryEmpty')}</div>
+      ) : filter === 'artist' ? (
+        renderArtistGroups()
       ) : (
         <div className="album-grid-wrap">
-          {albums.map(album => {
-            const coverUrl = album.coverArt ? buildCoverArtUrl(album.coverArt, 300) : '';
-            const cacheKey = album.coverArt ? coverArtCacheKey(album.coverArt, 300) : '';
-            const trackCount = album.trackIds.filter(tid => !!offlineTracks[`${serverId}:${tid}`]).length;
-            return (
-              <div key={album.id} className="album-card card offline-library-card">
-                <div className="album-card-cover">
-                  {coverUrl ? (
-                    <CachedImage src={coverUrl} cacheKey={cacheKey} alt={`${album.name} Cover`} loading="lazy" />
-                  ) : (
-                    <div className="album-card-cover-placeholder">
-                      <HardDriveDownload size={32} />
-                    </div>
-                  )}
-                  <div className="album-card-play-overlay">
-                    <button
-                      className="album-card-details-btn"
-                      onClick={() => handlePlay(album.id)}
-                      aria-label={`${album.name} abspielen`}
-                    >
-                      <Play size={15} fill="currentColor" />
-                    </button>
-                  </div>
-                </div>
-                <div className="album-card-info">
-                  <p className="album-card-title truncate">{album.name}</p>
-                  <p className="album-card-artist truncate">{album.artist}</p>
-                  {album.year && <p className="album-card-year">{album.year}</p>}
-                  <div className="offline-library-card-meta">
-                    <button
-                      className="offline-library-enqueue"
-                      onClick={() => handleEnqueue(album.id)}
-                      title="Zur Warteschlange hinzufügen"
-                    >
-                      + Queue
-                    </button>
-                    <span className="offline-library-tracks">{trackCount} tracks</span>
-                    <button
-                      className="offline-library-delete"
-                      onClick={() => deleteAlbum(album.id, serverId)}
-                      data-tooltip={t('albumDetail.removeOffline')}
-                      data-tooltip-pos="top"
-                    >
-                      <Trash2 size={11} />
-                    </button>
-                  </div>
-                </div>
-              </div>
-            );
-          })}
+          {filtered.map(renderCard)}
         </div>
       )}
     </div>