docs: comprehensive README with incentive mechanism and validator guide

- Rewrite README with detailed system architecture
- Add mathematical formulas for weight calculation (softmax, linear)
- Document commit-reveal protocol and PBFT consensus
- Add score aggregation and outlier detection explanations
- Include security considerations and formal analysis
- Add docs/validator.md with setup instructions
- Hardware requirements: 16 vCPU, 64GB RAM, 500GB storage
- Document port 9000/TCP requirement

Author: EchoBT