Function create_runtime_temp_dir_guard 

pub async fn create_runtime_temp_dir_guard(
    temp_root: &str,
    scope: &str,
    cleanup_label: &'static str,
) -> Result<TempDirGuard, RuntimeTempDirError>

Creates a scope-local runtime temporary directory guarded by RAII cleanup.

The returned [aster_forge_utils::raii::TempDirGuard] removes the created directory on drop. This helper is intended for one operation, such as image rendering, archive extraction, or temporary external command output. It should not guard the shared _runtime root itself.