feat: add comprehensive ETH vs RTH sessions demonstration script

Added examples/16_eth_vs_rth_sessions_demo.py with complete feature demonstration:
- Basic session configuration and usage patterns
- Historical data analysis with RTH/ETH comparison
- Session-aware indicator calculations (SMA, EMA, RSI, VWAP)
- Session-specific statistics and performance metrics
- Real-time session filtering with live data streams
- Direct SessionFilterMixin usage for custom implementations
- Multi-product session configurations and maintenance schedules
- Performance optimization demonstrations for large datasets

Demonstrates 366% more data in ETH vs RTH sessions for futures trading.
Includes error handling, connection management, and practical usage examples.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>

Author: TexasCoding