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/validator/lib/isSlug.js

@@ -0,0 +1,15 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.default = isSlug;
+var _assertString = _interopRequireDefault(require("./util/assertString"));
+function _interopRequireDefault(e) { return e && e.__esModule ? e : { default: e }; }
+var charsetRegex = /^[a-z0-9](?!.*[-_]{2,})(?:[a-z0-9_-]*[a-z0-9])?$/;
+function isSlug(str) {
+  (0, _assertString.default)(str);
+  return charsetRegex.test(str);
+}
+module.exports = exports.default;
+module.exports.default = exports.default;