- threshold: fix crash when display is None (_format_display now falls
back to default format string instead of calling None.format())
- threshold: shorten notification messages by stripping plugin-name prefix
from metric_path (cpu_percent instead of cpu_monitor.cpu_percent)
- main: demote aiohttp.access log records from INFO to DEBUG
- udp: replace debug print with proper logger.info for new host sign-on
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>