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/src/utils/logger.js

@@ -0,0 +1,27 @@
+const winston = require('winston');
+
+const logger = winston.createLogger({
+  level: process.env.LOG_LEVEL || 'info',
+  format: winston.format.combine(
+    winston.format.timestamp({ format: 'YYYY-MM-DD HH:mm:ss' }),
+    winston.format.errors({ stack: true }),
+    winston.format.splat(),
+    winston.format.json()
+  ),
+  defaultMeta: { service: 'landvex-api' },
+  transports: [
+    new winston.transports.File({ filename: 'logs/error.log', level: 'error' }),
+    new winston.transports.File({ filename: 'logs/combined.log' })
+  ]
+});
+
+if (process.env.NODE_ENV !== 'production') {
+  logger.add(new winston.transports.Console({
+    format: winston.format.combine(
+      winston.format.colorize(),
+      winston.format.simple()
+    )
+  }));
+}
+
+module.exports = logger;