Report malformed Hermes and DeepSeek Harness documents as YAML. Carry the compiled setup/uninstall diagnostics coverage from #2153 onto the existing validation from #2157, including unchanged files and no backup writes. Add malformed YAML scenarios for both clients. Validation: 174 focused tests, npm run check, test discovery, package verification, and npm pack --dry-run. Co-authored-by: Jax367 <[email protected]>