Checklist

• I added a descriptive title
• I searched open requests and couldn't find a duplicate

What is the idea?

Implement a step summary (and include the same report in the PR) describing the files templated (the stubs they requested/used) and any unused stubs.

Why is this needed?

Improved transparency on where files come from and how they get rendered.

What should happen?

Update template-files to produce a GITHUB_STEP_SUMMARY at the end of the job. This summary will then be accessible at the completion of the workflow in the GH Action summary page. We'd also like to include this info in the PR that gets created for easier audits.

Additional Context

No response