fix: ép render lại sau khi resize cửa sổ (on-demand)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/app/components/VirtualTour.tsx

@@ -1457,6 +1457,7 @@ function TourExperience({
       camera.aspect = width / height;
       camera.updateProjectionMatrix();
       renderer.setSize(width, height);
+      needsRenderRef.current = true;
       updateHotspots();
     };