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-v2/node_modules/tar-stream/sandbox.js

@@ -0,0 +1,11 @@
+const tar = require('tar-stream')
+const fs = require('fs')
+const path = require('path')
+const pipeline = require('pump') // eequire('stream').pipeline
+
+fs.createReadStream('test.tar')
+  .pipe(tar.extract())
+  .on('entry', function (header, stream, done) {
+    console.log(header.name)
+    pipeline(stream, fs.createWriteStream(path.join('/tmp', header.name)), done)
+  })