Show QR image and Download PNG button in QR Codes panel; v1.1.3

Each QR code card now renders a 128px preview of the actual QR image
(pointing to /qr/<slug> on the current origin) and a Download PNG link
that saves it as qr-<label>.png. Uses the qrcode browser build with
@types/qrcode for TypeScript support.

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

package.json

@@ -1,7 +1,7 @@
 {
   "name": "siteforge",
   "private": true,
-  "version": "1.1.2",
+  "version": "1.1.3",
   "type": "module",
   "scripts": {
     "dev": "vite",
@@ -40,6 +40,7 @@
   "devDependencies": {
     "@eslint/js": "^9.39.4",
     "@types/node": "^24.12.0",
+    "@types/qrcode": "^1.5.6",
     "@types/react": "^19.2.14",
     "@types/react-dom": "^19.2.3",
     "@vitejs/plugin-react": "^6.0.0",