docs: update README.md with version 0.1.1 and new features

- Update version from 0.1.0 to 0.1.1 in installation section
- Add new features: real-time monitoring, trading modes, risk management
- Add working examples using official Hyperliquid Rust SDK
- Update quick start with working data fetching and backtesting examples
- Add real-time monitoring example with alerts and performance tracking
- Enhance usage guide with trading modes, monitoring, and risk management
- Reorganize examples section with working examples as recommended starting points
- Add unified data interface documentation
- Update performance metrics and stability guarantees
- Enhance disclaimer with paper trading and risk control recommendations

Author: xsa-dev