Update nthpartyfinder project page, clean up repo hygiene

- Update docs/projects/nthpartyfinder/index.html with latest content
- Remove .cache/ from git tracking (already in .gitignore)
- Add MEMORY/, node_modules/, .zerg/, .gsd/ to .gitignore
- Add package.json with Playwright test dependency

Co-Authored-By: Paperclip <noreply@paperclip.ing>

Author: p4gs