fix: remove click-outside-to-close on info/metadata modal

The backdrop click handler was too easy to trigger accidentally,
especially when editing fields. Close button handles dismissal.

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

src/ui.js

@@ -280,10 +280,6 @@ export function closeInfoModal() {
   S.infoSong = null;
   S._infoArtData = null;
 }
-document.addEventListener('click', e => {
-  const m = document.getElementById('info-modal');
-  if(m.classList.contains('open') && e.target===m) closeInfoModal();
-});
 
 function _leaveEditMode() {
   document.getElementById('info-view-mode').style.display = '';