Function confirm_authenticated 

async fn confirm_authenticated(
    cli_path: &str,
    args: &[String],
    env: &HashMap<String, String>,
) -> bool

Run the provider’s auth-check subcommand and return true if it exits 0. Failure modes (binary missing, network error, etc.) are all treated as “not authenticated” — the caller will then either keep waiting (drain task loop) or transition to Failed (exit fallback).