The two Debian-family CA-layout constants lived in
docker/provision/ca.py, which forced the smolmachines backend to
import them cross-backend (smolmachines -> docker). Move them into
the shared backend/util.py next to select_ca_cert; docker, compose,
and smolmachines now all import from there. No behavior change.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Both backends' provision_ca duplicated _select_ca_cert and the
SHA-256 fingerprint computation verbatim. Lift them into the shared
backend/util.py as select_ca_cert + log_ca_fingerprint; docker and
smolmachines now call the shared helpers. No behavior change.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>