Rewrite README with proper attribution and actual project documentation

- Replace HKUDS original README with project-specific documentation
- Add fork attribution: "Based on HKUDS/AI-Researcher"
- Document skill system, memory system, and project structure
- Fix Quick Start with correct Docker image and run commands
- Update setup.cfg author to "Lihua (based on HKUDS/AI-Researcher)"
- Keep original citation and license attribution

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: LIHUA919