Function run_exec 

pub async fn run_exec(
    command: String,
    args: Vec<String>,
    cwd: PathBuf,
    prompt_text: String,
    permission_mode: PermissionMode,
    output_format: &str,
    timeout_secs: Option<u64>,
    prompt_retries: u32,
    suppress_reads: bool,
) -> Result<i32>

Run a non-interactive exec command (no session persistence).