The sweep exercises usb/employees handlers, which default to EXTERNAL
directory mode when no setting row exists - green on the dev box where
the external MySQL databases happen to exist, red in CI where they do
not. Seed selfhosted mode in an autouse fixture so the guard is
deterministic everywhere. Verified by running the suite with the
external DB hosts pointed at an unreachable address.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>