Function run_captured 

pub fn run_captured(
    command: &str,
    cwd: &Utf8Path,
    env: &[(String, String)],
    log_path: &Utf8Path,
) -> Result<(i32, String)>

Run a one-shot shell command, capturing stdout (for state refs) while still logging both streams. Unlike run_foreground, output does not go to the terminal — checkpoint machinery consumes it instead.