Function generate_prd_with_model_retry 

pub async fn generate_prd_with_model_retry(
    task: &str,
    okr: &Okr,
    primary_provider: Arc<dyn Provider>,
    primary_model: &str,
    registry: Option<&ProviderRegistry>,
) -> Result<Prd>

Generate a PRD with automatic model retry on failure. Tries the primary model first, then attempts alternative models if it fails. This makes autonomous execution more robust against transient provider issues.