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/strip-bom/index.js

@@ -0,0 +1,15 @@
+'use strict';
+
+module.exports = string => {
+	if (typeof string !== 'string') {
+		throw new TypeError(`Expected a string, got ${typeof string}`);
+	}
+
+	// Catches EFBBBF (UTF-8 BOM) because the buffer-to-string
+	// conversion translates it to FEFF (UTF-16 BOM)
+	if (string.charCodeAt(0) === 0xFEFF) {
+		return string.slice(1);
+	}
+
+	return string;
+};