Update documentation for new features:
- Add CHANGELOG entries for research features and privacy enhancements
- Update README with new CLI commands and security features
- Add privacy-security.md documentation for PII detection
- Add research-features.md for narrative and outcome tracking
- Add architecture, CI/CD, CLI reference documentation
- Update installation, operations, and quick-start guides
- Add Jupyter workflow and queue documentation
- New landing page and research runner plan