Function poll_device_code 

pub async fn poll_device_code(
    device_auth_id: &str,
    user_code: &str,
) -> Result<(String, String), CodexError>

Poll once for device authorization completion.

On success returns (authorization_code, server_issued_pkce_verifier) — feed both into exchange_code. While the user has not yet approved, returns CodexError::AuthorizationPending.

Errors

• CodexError::AuthorizationPending while waiting for the user.
• CodexError::Api on expired or invalid device codes.