Nexus IoT Unified Controller

You are building a middleware for a smart home hub that must integrate with devices from various manufacturers using different protocols (Zigbee, WiFi, Bluetooth). The system should allow users to create 'Scenes' (e.g., 'Movie Night' dims lights and closes blinds simultaneously). It must be easy to add new device types without changing the Scene controller logic. Design the class structure for device communication and scene execution.