Add presentation document for NotebookLM podcast generation (#4)

* Add presentation for NotebookLM podcast generation

Structured document covering 7 key features of the reference repo:
- CBA (Codebase Agent)
- Memory System (Modular Context)
- Issue-to-PR Automation
- Layered Architecture Patterns
- Security Patterns
- Testing Patterns
- CI/CD for Documentation

Target audience: Principal engineers evaluating AI-assisted development

* docs: refresh presentation with new features from PR #5

Add Feature 8 (Self-Review Reflection) and Feature 9 (Proactive GHA Workflows)
to reflect the patterns merged in PR #5. Update adoption table and summary to
cover all 9 features. Add cross-reference from Feature 3 to Feature 9.

Author: jeremyeder