Function run_eval 

pub async fn run_eval(
    eval_name: &str,
    eval: &AiEval,
    model: &str,
    variant: &str,
    provider_url: &str,
    auth_header: Option<&str>,
    provider_model: &str,
    system_message: Option<&str>,
    timeout_ms: u64,
) -> EvalRunResult

Run an eval against a model alias (DW-086). The provider_url is the full URL, auth_header is the optional Authorization header, provider_model is the provider’s own model identifier, and system_message is the optional prompt-version system message (from the eval’s prompt reference, resolved by the caller). Returns the per-case results.