fix: Random Mix improvements, queue UX fixes (v1.4.3)

- Random Mix: remove redundant Play All button in genre mix section
- Random Mix: Play All disabled with live counter during genre mix loading
- Random Mix: cap genre fetch at 50 genres to prevent over-fetching
- Random Mix: cache-bust getRandomSongs to always get fresh results
- Random Mix: clear songs on remix to fix display/play mismatch
- Queue: show song count and total duration in header
- Queue: context-active class keeps hover highlight on right-click
- Context Menu: add Favorite option for queue-item type

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

src/components/ContextMenu.tsx

@@ -215,6 +215,9 @@ export default function ContextMenu() {
                   <Disc3 size={14} /> {t('contextMenu.openAlbum')}
                 </div>
               )}
+              <div className="context-menu-item" onClick={() => handleAction(() => star(song.id, 'song'))}>
+                <Star size={14} /> {t('contextMenu.favorite')}
+              </div>
               <div className="context-menu-item" onClick={() => handleAction(() => startRadio(song.artist, song.artist))}>
                 <Radio size={14} /> {t('contextMenu.startRadio')}
               </div>