Add furniture click events, OrbitControls toggle, and floor change event

- Export COLORS for external module access (themes)
- Extend _onClick to detect furniture clicks before room clicks,
  dispatching 'furnitureclick' with catalog/room/mesh details
- Add setControlsEnabled(enabled) to toggle OrbitControls
- Dispatch 'floorchange' event from showFloor()
- Wire up furnitureclick in index.html to show item info

src/index.html

@@ -151,6 +151,11 @@
     viewer.addEventListener('roomclick', (e) => {
       selectRoom(e.detail.roomId);
     });
+
+    viewer.addEventListener('furnitureclick', (e) => {
+      const d = e.detail;
+      document.getElementById('info').textContent = `${d.itemName} — in ${renderer.getRooms().find(r => r.id === d.roomId)?.name || d.roomId}`;
+    });
   </script>
 </body>
 </html>