Implement bridge and script modes for wsssht

- Added run_bridge_mode() function with JSON stdin/stdout interface
- Added run_script_mode() function with JSON protocol for scripting
- Bridge mode: JSON communication between stdin/stdout and WebSocket
- Script mode: JSON status updates, command processing, and monitoring
- Both modes provide structured JSON output for programmatic use
- Fixed compilation warnings and ensured clean build
- All operating modes now fully implemented