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-admin-api/node_modules/iconv-lite/lib/bom-handling.js

@@ -0,0 +1,52 @@
+"use strict";
+
+var BOMChar = '\uFEFF';
+
+exports.PrependBOM = PrependBOMWrapper
+function PrependBOMWrapper(encoder, options) {
+    this.encoder = encoder;
+    this.addBOM = true;
+}
+
+PrependBOMWrapper.prototype.write = function(str) {
+    if (this.addBOM) {
+        str = BOMChar + str;
+        this.addBOM = false;
+    }
+
+    return this.encoder.write(str);
+}
+
+PrependBOMWrapper.prototype.end = function() {
+    return this.encoder.end();
+}
+
+
+//------------------------------------------------------------------------------
+
+exports.StripBOM = StripBOMWrapper;
+function StripBOMWrapper(decoder, options) {
+    this.decoder = decoder;
+    this.pass = false;
+    this.options = options || {};
+}
+
+StripBOMWrapper.prototype.write = function(buf) {
+    var res = this.decoder.write(buf);
+    if (this.pass || !res)
+        return res;
+
+    if (res[0] === BOMChar) {
+        res = res.slice(1);
+        if (typeof this.options.stripBOM === 'function')
+            this.options.stripBOM();
+    }
+
+    this.pass = true;
+    return res;
+}
+
+StripBOMWrapper.prototype.end = function() {
+    return this.decoder.end();
+}
+