OptionalauthReactive auth token source from the Studio's auth store.
Optionaltoken?: TokenSourceA reactive token source. The SDK subscribes and stays in sync — the Studio is the single authority for auth and handles token refresh.
Optional because older Studios may not expose it. When absent, the SDK falls back to localStorage/cookie discovery.
Studio-specific configuration for the SDK. When present, the SDK operates in studio mode and derives auth from the provided token source instead of discovering tokens independently.