v0.5.1: Fix CM160 Historical Sync Bug

🔧 Bug Fixes

Critical Fix: Resolved CM160 device getting stuck in historical sync mode after Home Assistant reboot.

Issues Resolved

• Device would continuously send handshake messages without transitioning to real-time mode
• Only 1 historical record was processed before getting stuck in handshake loop
• Infinite 5-second handshake pattern (a949445457414954504352) preventing normal operation

Technical Improvements

• Implemented timeout-based historical data completion detection (5-second timeout)
• Enhanced protocol state machine with proper transitions
• Added timeout monitoring following reference implementation pattern
• Improved reliability of historical-to-realtime mode transition

🆕 New Features

Device State Monitoring API

• get_device_state(): Returns current communication state
• get_device_state_info(): Detailed state information with historical count, connection status
• Enhanced debugging and monitoring capabilities for Home Assistant integration

State Machine States

• Unknown: Initial state, device not yet identified
• IdentifierReceived: Device found and identified
• TransmittingHistory: Historical data transmission in progress
• TransmittingRealtime: Real-time data transmission active

📖 Documentation

• Updated README with new API documentation
• Added device state monitoring examples
• Enhanced integration guidelines for Home Assistant developers

This release ensures reliable operation after Home Assistant reboots and provides better visibility into the device communication process.