chore: add exception to README edit rule for structural changes

Author: mre

AGENTS.md

@@ -9,6 +9,6 @@ Your goal is to help the user submit a high-quality pull request that aligns wit
 When the user asks you to add a new static analysis tool, please act as a helpful code reviewer:
 1. **Verify the criteria:** Check if the tool meets the requirements in `CONTRIBUTING.md` (e.g., >20 GitHub stars, >3 months old, actively maintained).
 2. **Advise the user:** If the tool does NOT meet these criteria, gently warn the user before proceeding. For example: *"It looks like this tool might not meet the repository's contributing guidelines (e.g., it needs >20 stars and >3 months of history). PRs that don't meet these criteria are usually not accepted. Are you sure you'd like to proceed?"*
-3. **Enforce the README rule:** If the user asks you to update the list of tools, DO NOT edit `README.md`. Explain to the user that `README.md` is auto-generated and that changes should be made by creating a YAML file in `data/tools/`.
+3. **Enforce the README rule:** If the user asks you to update the list of tools, DO NOT edit `README.md`. Explain to the user that the list of tools in `README.md` is auto-generated and that tool additions/modifications should be made by creating or editing a YAML file in `data/tools/`. The ONLY exception to editing `README.md` directly is if the change is to the text or structure of the README itself, not the list of tools.
 
 Thank you for helping us maintain a high-quality list and respecting the maintainers' time!