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/components/AlbumHeader.tsx

@@ -143,8 +143,8 @@ export default function AlbumHeader({
               <button
                 className="album-detail-cover-btn"
                 onClick={() => setLightboxOpen(true)}
-                data-tooltip="Vergrößern"
-                aria-label={`${info.name} Cover vergrößern`}
+                data-tooltip={t('albumDetail.enlargeCover')}
+                aria-label={`${info.name} ${t('albumDetail.enlargeCover')}`}
               >
                 <CachedImage className="album-detail-cover" src={coverUrl} cacheKey={coverKey} alt={`${info.name} Cover`} />
               </button>