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/safe-stable-stringify/index.d.ts

@@ -0,0 +1,22 @@
+export type Replacer = (number | string)[] | null | undefined | ((key: string, value: unknown) => string | number | boolean | null | object)
+
+export function stringify(value: undefined | symbol | ((...args: unknown[]) => unknown), replacer?: Replacer, space?: string | number): undefined
+export function stringify(value: string | number | unknown[] | null | boolean | object, replacer?: Replacer, space?: string | number): string
+export function stringify(value: unknown, replacer?: ((key: string, value: unknown) => unknown) | (number | string)[] | null | undefined, space?: string | number): string | undefined
+
+export interface StringifyOptions {
+  bigint?: boolean,
+  circularValue?: string | null | TypeErrorConstructor | ErrorConstructor,
+  deterministic?: boolean | ((a: string, b: string) => number),
+  maximumBreadth?: number,
+  maximumDepth?: number,
+  strict?: boolean,
+}
+
+export namespace stringify {
+  export function configure(options: StringifyOptions): typeof stringify
+}
+
+export function configure(options: StringifyOptions): typeof stringify
+
+export default stringify