Function default_registry 

pub fn default_registry(
    template_config: &PreprocessorTemplateSection,
    pather: &dyn Pather,
) -> Result<PreprocessorRegistry>

The default registry used on the normal execution path.

Contains all user-facing preprocessors:

• unarchive::UnarchivePreprocessor for .tar.gz extraction
• template::TemplatePreprocessor for Jinja2-style templates

The identity preprocessor is test-only and is intentionally not registered here (it would match innocuous-looking .identity files in user dotfiles).