feat: implement status monitoring, fault detection, and comms watchdog

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

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

@@ -62,13 +62,13 @@ Implementation of ESP32-C6 based AC controller that bridges Zigbee (Home Assista
 - [x] Update Readme.md
 
 ### Task 5: Status Monitoring and Feedback
-- [ ] Implement AC status polling via UART (temperature, mode, etc.)
-- [ ] Map MideaUART status to ZCL attributes for reporting
-- [ ] Implement error handling and fault detection
-- [ ] Add watchdog for communication timeouts
-- [ ] Write unit tests for status monitoring and error paths
-- [ ] Run tests - must pass before next task
-- [ ] Update Readme.md
+- [x] Implement AC status polling via UART (temperature, mode, etc.)
+- [x] Map MideaUART status to ZCL attributes for reporting
+- [x] Implement error handling and fault detection
+- [x] Add watchdog for communication timeouts
+- [x] Write unit tests for status monitoring and error paths
+- [x] Run tests - must pass before next task
+- [x] Update Readme.md
 
 ### Task 6: End-to-End Integration and Testing
 - [ ] Integrate all layers: Zigbee ←→ Integration ←→ UART