docs(sbom): link reviewer route contract automation

[stacknil]

Summary

• add the SBOM reviewer-route contract section to the SBOM reviewer path
• link the reviewer-route contract to both the local validator and CI workflow
• include Markdown files in the LF line-ending policy for deterministic reviewer docs

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 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