Fix QR image not appearing for new codes; v1.1.4

Switch from toDataURL (which silently failed in browser) to toCanvas on
a real <canvas> ref — more reliable and renders immediately on mount.
Download PNG link appears once the canvas is drawn.

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

package.json

@@ -1,7 +1,7 @@
 {
   "name": "siteforge",
   "private": true,
-  "version": "1.1.3",
+  "version": "1.1.4",
   "type": "module",
   "scripts": {
     "dev": "vite",