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/openai/internal/headers.d.mts

@@ -0,0 +1,20 @@
+type HeaderValue = string | undefined | null;
+export type HeadersLike = Headers | readonly HeaderValue[][] | Record<string, HeaderValue | readonly HeaderValue[]> | undefined | null | NullableHeaders;
+declare const brand_privateNullableHeaders: unique symbol;
+/**
+ * @internal
+ * Users can pass explicit nulls to unset default headers. When we parse them
+ * into a standard headers type we need to preserve that information.
+ */
+export type NullableHeaders = {
+    /** Brand check, prevent users from creating a NullableHeaders. */
+    [brand_privateNullableHeaders]: true;
+    /** Parsed headers. */
+    values: Headers;
+    /** Set of lowercase header names explicitly set to null. */
+    nulls: Set<string>;
+};
+export declare const buildHeaders: (newHeaders: HeadersLike[]) => NullableHeaders;
+export declare const isEmptyHeaders: (headers: HeadersLike) => boolean;
+export {};
+//# sourceMappingURL=headers.d.mts.map