Function engine_basenames_for_sm 

pub(crate) fn engine_basenames_for_sm(
    engine_dir: &Path,
    sm: Option<&str>,
) -> Result<Vec<String>>

Returns sorted basenames of .engine files under engine_dir that match the requested SM, or all .engine basenames when sm is None.

Used for operator-visible logs before TRT prewarm; filenames are not a reliable (batch, seq) key for dynamic models (see CLAUDE.md).