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/isJWT.js

@@ -0,0 +1,15 @@
+import assertString from './util/assertString';
+import isBase64 from './isBase64';
+export default function isJWT(str) {
+  assertString(str);
+  var dotSplit = str.split('.');
+  var len = dotSplit.length;
+  if (len !== 3) {
+    return false;
+  }
+  return dotSplit.reduce(function (acc, currElem) {
+    return acc && isBase64(currElem, {
+      urlSafe: true
+    });
+  }, true);
+}