Function render_actor 

pub fn render_actor(
    base_url: &str,
    preferred_username: &str,
    display_name: &str,
    summary: Option<&str>,
    pubkey_pem: &str,
) -> Actor

Render an Actor document for the pod at base_url. base_url is the scheme+host only (e.g. https://pod.example). The document exposes endpoints relative to /profile/card.jsonld, matching JSS.

preferred_username is the WebFinger local-part; display_name is the human-facing label. pubkey_pem must already be PEM-encoded (either freshly generated via generate_actor_keypair or loaded from disk).