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/lib/changelog.ts

@@ -1,5 +1,5 @@
 // Mirrors CHANGELOG.md at the repo root — update both together.
-export const APP_VERSION = "0.21.0";
+export const APP_VERSION = "0.22.0";
 
 export type ChangelogEntry = {
   version: string;
@@ -11,6 +11,13 @@ export type ChangelogEntry = {
 };
 
 export const CHANGELOG: ChangelogEntry[] = [
+  {
+    version: "0.22.0",
+    date: "2026-07-13 22:49",
+    added: [
+      "**QR code on printed shopping lists**: a public list's printout now includes a scannable code linking back to the live version — pairs with public-editable links, so someone at the store can scan and check items off in real time.",
+    ],
+  },
   {
     version: "0.21.0",
     date: "2026-07-13 22:34",