feat: QR code on printed shopping lists

Added the qrcode package (server-side data-URL generation, no client
JS) rather than hand-rolling QR encoding. Only rendered when the list
is public — a private list's /s/ link 404s for anyone who isn't the
owner, so a QR code there would just be a dead scan.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

apps/web/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@epicure/web",
-  "version": "0.21.0",
+  "version": "0.22.0",
   "private": true,
   "scripts": {
     "dev": "next dev",
@@ -38,6 +38,7 @@
     "next-intl": "^4.13.0",
     "next-themes": "^0.4.6",
     "nodemailer": "^9.0.1",
+    "qrcode": "^1.5.4",
     "react": "19.2.4",
     "react-dom": "19.2.4",
     "react-hook-form": "^7.80.0",
@@ -56,6 +57,7 @@
     "@testing-library/react": "^16.3.2",
     "@types/node": "^20.19.43",
     "@types/nodemailer": "^8.0.1",
+    "@types/qrcode": "^1.5.6",
     "@types/react": "^19",
     "@types/react-dom": "^19",
     "@types/web-push": "^3.6.4",