Function execute_run 

pub async fn execute_run(
    path: &str,
    trace: bool,
    denied_builtins: HashSet<String>,
    script_argv: Vec<String>,
    skill_dirs_raw: Vec<String>,
    llm_mock_mode: CliLlmMockMode,
    attestation: Option<RunAttestationOptions>,
) -> RunOutcome

In-process equivalent of run_file_with_skill_dirs. Returns the captured stdout, stderr, and what exit code the binary entry would have used, instead of writing to real stdout/stderr or calling process::exit.

Tests should call this directly. The harn run binary path wraps it.