Function execute_in_session 

pub async fn execute_in_session(
    pool_key: &str,
    initial_cwd: Option<&str>,
    command: &str,
    command_cwd: Option<&str>,
    timeout_secs: Option<u64>,
    tx: Sender<StreamChunk>,
) -> Result<StreamingCommandResult>

Execute a shell command inside a reusable PTY-backed session.