fix arrow spawning and suppress step labels during calibration

ArrowGame: use ref for onSongEnd to avoid unstable deps causing the
audio effect to re-run and lose songStartRef. Reset arrows, combo,
and spawn index when the game starts. Log audio play failures instead
of swallowing them.

GestureOverlay: only show 'arms-out' label during calibration, not
step labels which are confusing before the game starts.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/components/GestureOverlay.tsx

@@ -17,9 +17,11 @@ interface Props {
 export function GestureOverlay({ gesture, calibrationStatus, framingHint }: Props) {
   if (calibrationStatus === 'ready') return null
 
+  const showGesture = gesture === 'arms-out'
+
   return (
     <>
-      {gesture && (
+      {showGesture && (
         <div className="gesture-label">
           {GESTURE_LABELS[gesture]}
         </div>

src/game/ArrowGame.tsx

@@ -60,6 +60,8 @@ export const ArrowGame = forwardRef<ArrowGameHandle, Props>(({ active = true, ch
   const audioRef = useRef<HTMLAudioElement | null>(null)
   const songStartRef = useRef<number | null>(null)
   const spawnedUpToRef = useRef(0)
+  const onSongEndRef = useRef(onSongEnd)
+  onSongEndRef.current = onSongEnd
 
   const showJudgment = useCallback((text: string) => {
     if (judgmentTimer.current) clearTimeout(judgmentTimer.current)
@@ -140,16 +142,24 @@ export const ArrowGame = forwardRef<ArrowGameHandle, Props>(({ active = true, ch
   useEffect(() => {
     if (!active || !chartNotes || !audioUrl) return
 
+    // Reset state for fresh start
+    arrowsRef.current = []
+    setArrows([])
+    spawnedUpToRef.current = 0
+    comboRef.current = 0
+    setScore({ perfect: 0, good: 0, miss: 0, combo: 0 })
+
     const audio = new Audio(audioUrl)
     audioRef.current = audio
     songStartRef.current = null
-    spawnedUpToRef.current = 0
 
     audio.play().then(() => {
       songStartRef.current = performance.now()
-    }).catch(() => {})
+    }).catch((e) => {
+      console.warn('Audio play failed:', e)
+    })
 
-    audio.addEventListener('ended', () => onSongEnd?.())
+    audio.addEventListener('ended', () => onSongEndRef.current?.())
 
     return () => {
       audio.pause()
@@ -157,7 +167,7 @@ export const ArrowGame = forwardRef<ArrowGameHandle, Props>(({ active = true, ch
       audioRef.current = null
       songStartRef.current = null
     }
-  }, [active, chartNotes, audioUrl, onSongEnd])
+  }, [active, chartNotes, audioUrl]) // eslint-disable-line react-hooks/exhaustive-deps
 
   // Chart mode: spawn arrows based on song time
   useEffect(() => {