Render QR code on finished series page; v2.0.34

The downloadQrUrl field was saved but never displayed — add the QR image
below the action buttons, wrapped in a link to the download URL.

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

package.json

@@ -1,7 +1,7 @@
 {
   "name": "siteforge",
   "private": true,
-  "version": "2.0.33",
+  "version": "2.0.34",
   "type": "module",
   "scripts": {
     "dev": "vite",