swipe bug fix

frontend/src/components/ImageLightbox.jsx

@@ -4,15 +4,16 @@ import { createPortal } from 'react-dom';
 export default function ImageLightbox({ src, onClose }) {
   const overlayRef = useRef(null);
 
-  // Close on Escape
+  // Close on Escape; signal global pinch handler to stand down while open
   useEffect(() => {
     const handler = (e) => { if (e.key === 'Escape') onClose(); };
     window.addEventListener('keydown', handler);
-    // Prevent body scroll while open
     document.body.style.overflow = 'hidden';
+    document.documentElement.dataset.lightboxOpen = '1';
     return () => {
       window.removeEventListener('keydown', handler);
       document.body.style.overflow = '';
+      delete document.documentElement.dataset.lightboxOpen;
     };
   }, [onClose]);