feat(queue): unified persistent queue list with playing indicator

Show all queue entries (played and upcoming) in one list instead of
splitting into a "Now playing" card + "Next up" tail, so previously
played tracks don't disappear and reappear when navigating back/forward.
The current track is outlined and shows a reusable "hopping bars"
PlayingIndicator (modern-sk style equalizer animation) for future reuse
across track lists.

src/i18n/locales/en.ts

@@ -138,9 +138,7 @@ const en = {
     close: 'Close',
     from: 'From {{source}}',
     radio: 'Radio · {{source}}',
-    nowPlaying: 'Now playing',
     nextUp: 'Next up',
-    nothingNext: 'Nothing queued next',
     empty: 'Queue is empty',
     radioActive: 'Radio active',
     mixing: '∞ mixing',