docs: Complete professional README with all features documented

- Project overview and purpose
- Feature table: endpoint discovery, param discovery, AI reasoning,
  test generation, vuln detection, tool integrations, deduplication
- Architecture diagram showing all 4 pipeline phases
- Tool integration details (Dirsearch, Arjun, Nuclei, SQLMap)
- Installation guides: uv, pip, Docker
- Configuration for OpenAI, Anthropic, and Nebius providers
- Full CLI reference with flags and example commands
- Docker build and run instructions with docker-compose
- Terminal output example showing real-time agent interface
- Project structure tree with file descriptions
- Future improvements roadmap

Author: vishnurajkv