- Replace all Unicode arrows/checkmarks (-> [OK] [FAIL]) in ach_server.py
and client.py log calls — Windows cp1252 console can't encode them
- Fix DeviceInfo attribute: serial_number -> serial
- Fix _device_info_to_dict key: serial_number -> serial
- Demote count_events 1E/1F per-key log lines from WARNING to DEBUG
(they were flooding the console on devices with many stored events)
- FileHandler now opens with encoding='utf-8' so session log files
can hold any characters without codec errors
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>