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

node_modules/http-proxy-middleware/dist/status-code.js

@@ -0,0 +1,23 @@
+export function getStatusCode(errorCode) {
+    let statusCode;
+    if (/HPE_INVALID/.test(errorCode)) {
+        statusCode = 502;
+        return statusCode;
+    }
+    if (/HPM_ERR_INVALID_MULTIPART_/.test(errorCode)) {
+        statusCode = 400;
+        return statusCode;
+    }
+    switch (errorCode) {
+        case 'ECONNRESET':
+        case 'ENOTFOUND':
+        case 'ECONNREFUSED':
+        case 'ETIMEDOUT':
+            statusCode = 504;
+            break;
+        default:
+            statusCode = 500;
+            break;
+    }
+    return statusCode;
+}