Turn off only the services you name

mobai-ci sim boot --slim-only <list> turns off just the listed iOS background services and leaves everything else running. Entries are launchd labels or simslim category ids:

mobai-ci sim boot --slim-only widgets
mobai-ci sim boot --slim-only com.apple.chronod

The change is applied before the simulator's first boot, so it costs nothing extra. --slim <profile.json> works as before; the two cannot be combined.