fix(machine): declare qrcode where electron/fund-atm.ts actually uses it

The fund-atm esbuild bundle imports `qrcode`, but apps/machine never
declared it — it resolved only through packages/nostr-client's
devDependency, which 763817b removed along with the dead scripts that
were the only reason it was there. The full `pnpm build` then failed at
its last step ("Could not resolve qrcode"), which is what the nix image
build runs. Declared (with @types/qrcode) in the package that imports it.

apps/machine/package.json

@@ -50,11 +50,13 @@
     "@tailwindcss/vite": "^4.0.0",
     "@types/better-sqlite3": "^7.0.0",
     "@types/node": "^22.0.0",
+    "@types/qrcode": "^1.5.6",
     "@vitejs/plugin-vue": "^5.2.0",
     "concurrently": "^9.0.0",
     "electron": "^33.0.0",
     "electron-builder": "^25.0.0",
     "esbuild": "^0.27.4",
+    "qrcode": "^1.5.4",
     "tailwindcss": "^4.0.0",
     "tw-animate-css": "^1.4.0",
     "typescript": "^5.7.0",