Function execute_run_json 

pub async fn execute_run_json(
    path: &str,
    trace: bool,
    denied_builtins: HashSet<String>,
    script_argv: Vec<String>,
    skill_dirs_raw: Vec<String>,
    llm_mock_mode: CliLlmMockMode,
    attestation: Option<RunAttestationOptions>,
    profile: RunProfileOptions,
    out: Box<dyn Write + Send>,
    options: RunJsonOptions,
) -> RunOutcome

execute_run variant for --json mode. Returns once the run is complete; the NDJSON event stream — including the terminal result or error event — has already been written to out and flushed. out must be Send because the run-event sink may be called from any worker thread the VM spawns.