pub fn kernel_source_dir(model_dir: &Path) -> Result<PathBuf, LayoutError>Expand description
2026-09-26: [model] kernel_source of <model_dir>/MODEL.toml,
validated: the referent is a sibling model directory holding a MODEL.toml
that does not redirect. Returns the source model directory (the model’s
own when there is no redirect). A model directory with no MODEL.toml owns
its own sources.