feat: Passwordless cross-device authentication

- Arkitektur: docs/auth/passwordless-architecture.md
- Backend: iom/quixzoom-auth-service/ (FastAPI + Redis)
- Webb: quixzoom-market-pages/se/login/ (QR-kod + polling)
- App: iom/quixzoom-app/src/features/auth/ (push + deep links)

Flöde: QR-kod → app-godkännande → webb-inloggad

landvex/node_modules/validator/es/lib/unescape.js

@@ -0,0 +1,8 @@
+import assertString from './util/assertString';
+export default function unescape(str) {
+  assertString(str);
+  return str.replace(/&quot;/g, '"').replace(/&#x27;/g, "'").replace(/&lt;/g, '<').replace(/&gt;/g, '>').replace(/&#x2F;/g, '/').replace(/&#x5C;/g, '\\').replace(/&#96;/g, '`').replace(/&amp;/g, '&');
+  // &amp; replacement has to be the last one to prevent
+  // bugs with intermediate strings containing escape sequences
+  // See: https://github.com/validatorjs/validator.js/issues/1827
+}