set_api_key
Set your FaceSign API key for this session. This must be called before any other FaceSign tools. Get your API key from the FaceSign dashboard. The key starts with sk_live_... or sk_test_... Optionally override the API server URL via `serverUrl` — intended for FaceSign developers pointing the SDK at a non-production backend (e.g. a dev server). Leave unset to use the default production API.
apiKey必填serverUrl