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/form-data/lib/populate.js

@@ -0,0 +1,10 @@
+'use strict';
+
+// populates missing values
+module.exports = function (dst, src) {
+  Object.keys(src).forEach(function (prop) {
+    dst[prop] = dst[prop] || src[prop]; // eslint-disable-line no-param-reassign
+  });
+
+  return dst;
+};