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/@sinonjs/commons/lib/class-name.js

@@ -0,0 +1,13 @@
+"use strict";
+
+/**
+ * Returns a display name for a value from a constructor
+ * @param  {object} value A value to examine
+ * @returns {(string|null)} A string or null
+ */
+function className(value) {
+    const name = value.constructor && value.constructor.name;
+    return name || null;
+}
+
+module.exports = className;