Standalone !services [host] command to check systemd service health.
Added help subcommand to both !sysinfo and !services showing usage,
configured hosts, and monitored services. Improved error messages
to guide users toward the right env vars when nothing is configured.
Fixes #3
Summary
!services [host]command to check systemd service health per hosthelpsubcommand to both!sysinfoand!servicesshowing usage, configured hosts, monitored services, and hints for env var configuration