- Add informative messages during graceful shutdown indicating what the server is waiting for
- Stop cleanup task immediately during shutdown to prevent keepalive timeouts
- Send tunnel close messages to ALL tunnels (both client and tool endpoints) during shutdown
- Import TUNNEL_CLOSE_MSG constant for proper tunnel closure
- Enhanced shutdown sequence with clear progress indicators
- Ensure all active connections receive proper shutdown notifications

This ensures wssshd provides clear feedback during shutdown and properly closes all tunnels without waiting for keepalive timeouts.