When no intercept mode is selected by flag or config, a new installation
on macOS or a Windows desktop edition uses "dns". Windows Server, iOS and
other platforms keep interface DNS mode unless intercept is selected
explicitly, and so does a config that cannot run in intercept mode.
Existing Standard installations are not switched on upgrade: ctrld-client
start marks the services it installs fresh, a service with neither a mode
nor the marker keeps interface DNS mode, and the macOS package pins such a
service to "off" explicitly. An explicit "off" stays final and is
persisted.
Master adaptation: the run flag and start install hunk move from
commands.go to commands_run.go and commands_service_start.go and use the
start command's logger and svcConfig; setDNS logs through p.Info(); the
flag test builds the run command with InitRunCmd; user-facing commands,
docs and the pkg test use the ctrld-client binary name.
Dev Scribe