test(docs): align reviewer route ci paths

[stacknil]

Summary

• add top-level sbom-diff-and-risk Markdown files to the reviewer-route CI path filters
• validate the reviewer-route workflow path filters from the existing route contract script
• document that the reviewer route contract checks workflow path-filter coverage
• normalize the reviewer-route workflow YAML with the repo LF policy

Validation

• python scripts\validate-reviewer-routes.py
• python -m py_compile scripts\validate-reviewer-routes.py
• git diff --cached --check
• git ls-files --eol -- .gitattributes .github/workflows/reviewer-route-contract-ci.yml scripts/validate-reviewer-routes.py tools/sbom-diff-and-risk/docs/reviewer-path.md

Privacy

• changed-file diff scanned for sensitive path, identity, and secret patterns