Add tutorial popup, footer, rules page with interactive diagrams
- Add TutorialPopup component with multi-step wizard and SGF-based diagrams
- Add Footer with Claude logo and AI transparency modal
- Create Rules page with interactive move navigation
- Add SGF parser utility for loading game diagrams
- Make Board component reactive to gameState changes
- Add modal/footer CSS styling
- Include SGF files for tutorial examples (single capture, group capture, scoring)
Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>