tweak: Faster marquee scroll speed

Reduced marquee animation duration:
- Min duration: 6s → 4s
- Per-character multiplier: 0.3s → 0.2s

A 20-character title now scrolls in ~8s instead of ~12s.

frontend/src/components/Player.tsx

@@ -163,7 +163,7 @@ export default function Player({ clip, isPlaying, onTogglePlay, onStop, onClose
 
   const progress = duration > 0 ? (currentTime / duration) * 100 : 0
   const displayTitle = clip.title || clip.prompt
-  const marqueeDuration = Math.max(6, displayTitle.length * 0.3)
+  const marqueeDuration = Math.max(4, displayTitle.length * 0.2)
 
   return (
     <>