Update the incorrect file name reference in the extra7 link from "extra9" to "extra7" to maintain consistency. Also refresh the docs README with new content including project introduction, roadmap, and navigation structure.
- Enhance chapter0-learning-map.md with new sections about project-based learning
- Refine README.md with updated project descriptions and roadmap
- Improve clarity and completeness of documentation
- Update image paths in documentation files to use relative paths
- Enhance README content with more detailed descriptions of chapters
- Fix sidebar link for CLI AI coding tools
sanbuphy