- Make AcLoggerOptions.AppType nullable; resolve AppType via config or DI default parameter
- Update AddAcLoggerFactory to accept host default AppType
- Enhance AcSignaRClientLogItemWriter: robust error handling, dropped log tracking, single error reporting per failure state
- Update logger README for new AppType precedence
- Document AcSignalRDataSource threading/event model in ISSUES
- Add diagnostic commands to settings.local.json