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/uuid/dist-node/stringify.js

@@ -0,0 +1,35 @@
+import validate from './validate.js';
+const byteToHex = [];
+for (let i = 0; i < 256; ++i) {
+    byteToHex.push((i + 0x100).toString(16).slice(1));
+}
+export function unsafeStringify(arr, offset = 0) {
+    return (byteToHex[arr[offset + 0]] +
+        byteToHex[arr[offset + 1]] +
+        byteToHex[arr[offset + 2]] +
+        byteToHex[arr[offset + 3]] +
+        '-' +
+        byteToHex[arr[offset + 4]] +
+        byteToHex[arr[offset + 5]] +
+        '-' +
+        byteToHex[arr[offset + 6]] +
+        byteToHex[arr[offset + 7]] +
+        '-' +
+        byteToHex[arr[offset + 8]] +
+        byteToHex[arr[offset + 9]] +
+        '-' +
+        byteToHex[arr[offset + 10]] +
+        byteToHex[arr[offset + 11]] +
+        byteToHex[arr[offset + 12]] +
+        byteToHex[arr[offset + 13]] +
+        byteToHex[arr[offset + 14]] +
+        byteToHex[arr[offset + 15]]).toLowerCase();
+}
+function stringify(arr, offset = 0) {
+    const uuid = unsafeStringify(arr, offset);
+    if (!validate(uuid)) {
+        throw TypeError('Stringified UUID is invalid');
+    }
+    return uuid;
+}
+export default stringify;