The onefile build is windowed (no console), so sys.stderr is None and uvicorn's
default logging dictConfig fails with "Unable to configure formatter 'default'",
which took the whole settings-panel server down (the BLE side kept working, but
the Settings window couldn't load). Pass log_config=None so uvicorn skips its own
logging setup — the daemon has its own file logger and doesn't need uvicorn's.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>