The new check drives host/teardown-host.sh for real — the first check in
the suite to execute a destructive script rather than grep it or run it
against shims. teardown-host honours an inherited BOX_YES, and test/cli.sh
never sanitised it, so under `BOX_YES=1 bash test/cli.sh` the invocation
took the consent arm instead of the gate: a real teardown of the host the
suite was running on, reported red only afterwards.
BOX_YES is the documented automation switch for this family, so an
operator's CI wrapper exporting it is the expected case, not a contrived
one. The file header promises the suite is runnable anywhere; before this
the promise held under any environment.
Fixed at the call site with `env -u BOX_YES`, plus a file-level `unset` so
the promise cannot be broken again by the next check that drives something
destructive.
Refs #113
ecce72f025