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/lodash/subtract.js

@@ -0,0 +1,22 @@
+var createMathOperation = require('./_createMathOperation');
+
+/**
+ * Subtract two numbers.
+ *
+ * @static
+ * @memberOf _
+ * @since 4.0.0
+ * @category Math
+ * @param {number} minuend The first number in a subtraction.
+ * @param {number} subtrahend The second number in a subtraction.
+ * @returns {number} Returns the difference.
+ * @example
+ *
+ * _.subtract(6, 4);
+ * // => 2
+ */
+var subtract = createMathOperation(function(minuend, subtrahend) {
+  return minuend - subtrahend;
+}, 0);
+
+module.exports = subtract;