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 <239124526+Jax367@users.noreply.github.com>
94153f1c75