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/redis-errors/lib/modern.js

@@ -0,0 +1,59 @@
+'use strict'
+
+const assert = require('assert')
+
+class RedisError extends Error {
+  get name () {
+    return this.constructor.name
+  }
+}
+
+class ParserError extends RedisError {
+  constructor (message, buffer, offset) {
+    assert(buffer)
+    assert.strictEqual(typeof offset, 'number')
+
+    const tmp = Error.stackTraceLimit
+    Error.stackTraceLimit = 2
+    super(message)
+    Error.stackTraceLimit = tmp
+    this.offset = offset
+    this.buffer = buffer
+  }
+
+  get name () {
+    return this.constructor.name
+  }
+}
+
+class ReplyError extends RedisError {
+  constructor (message) {
+    const tmp = Error.stackTraceLimit
+    Error.stackTraceLimit = 2
+    super(message)
+    Error.stackTraceLimit = tmp
+  }
+  get name () {
+    return this.constructor.name
+  }
+}
+
+class AbortError extends RedisError {
+  get name () {
+    return this.constructor.name
+  }
+}
+
+class InterruptError extends AbortError {
+  get name () {
+    return this.constructor.name
+  }
+}
+
+module.exports = {
+  RedisError,
+  ParserError,
+  ReplyError,
+  AbortError,
+  InterruptError
+}