feat: auto-close preview when main playback starts

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

src/main.js

@@ -129,6 +129,7 @@ window.addEventListener('load', () => {
   S.audio.addEventListener('play', () => {
     S._trackChanging = false;
     absInterrupt();
+    if (S.previewCurrent) stopPreview(false);
     setPlayIcon(true);
     document.getElementById('player-art').classList.add('spinning');
     if(navigator.mediaSession) navigator.mediaSession.playbackState = 'playing';