feat: Implement Zigbee-UART integration layer with message brokering, mode mapping, temperature conversion, and bidirectional status synchronization

docs/plans/2026-07-05-ballu-ac-esp32c6-controller-implementation.md

@@ -52,14 +52,14 @@ Implementation of ESP32-C6 based AC controller that bridges Zigbee (Home Assista
 - [x] Update Readme.md
 
 ### Task 4: Zigbee-UART Integration Layer
-- [ ] Create message broker between Zigbee and UART layers
-- [ ] Map ZCL system_mode to MideaUART MODE_* enums
-- [ ] Convert ZCL temperature (0.01°C) to MideaUART format
-- [ ] Implement bidirectional status synchronization
-- [ ] Handle command queuing and rate limiting (50ms spacing)
-- [ ] Write unit tests for mapping logic and error cases
-- [ ] Run tests - must pass before next task
-- [ ] Update Readme.md
+- [x] Create message broker between Zigbee and UART layers
+- [x] Map ZCL system_mode to MideaUART MODE_* enums
+- [x] Convert ZCL temperature (0.01°C) to MideaUART format
+- [x] Implement bidirectional status synchronization
+- [x] Handle command queuing and rate limiting (50ms spacing)
+- [x] Write unit tests for mapping logic and error cases
+- [x] Run tests - must pass before next task
+- [x] Update Readme.md
 
 ### Task 5: Status Monitoring and Feedback
 - [ ] Implement AC status polling via UART (temperature, mode, etc.)