feat: finalize documentation and validation (Task 7)

- Rewrite project CLAUDE.md to match actual C/Unity implementation and modules
- Add docs/hardware_connection_diagram.md (ESP32-C6 <-> Ballu AC wiring)
- Add docs/home_assistant_integration.md (HA usage examples)
- Update Readme.md doc index and fix unclosed code fence
- Validate docs against implementation (build + all tests pass)

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

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

@@ -80,12 +80,12 @@ Implementation of ESP32-C6 based AC controller that bridges Zigbee (Home Assista
 - [x] Update Readme.md
 
 ### Task 7: Documentation and Validation
-- [ ] Update CLAUDE.md with implementation details
-- [ ] Create hardware connection diagram in docs/
-- [ ] Add usage examples for Home Assistant integration
-- [ ] Validate all documentation against implementation
-- [ ] Final review and cleanup
-- [ ] Update Readme.md
+- [x] Update CLAUDE.md with implementation details
+- [x] Create hardware connection diagram in docs/
+- [x] Add usage examples for Home Assistant integration
+- [x] Validate all documentation against implementation
+- [x] Final review and cleanup
+- [x] Update Readme.md
 
 ## Technical Details