The upstream compose.host-ports.yml exists only from v1.0.0+, but the upgrade-tier base deploy is
the previous published version (0.2.0+), which predates it — so EXTRA_ENV's COMPOSE_FILE failed to
resolve on the base deploy (config --images rc=14, deploy FATA). install_steps.sh now copies a
cc-ci-owned identical overlay into the recipe checkout when absent, so 64738 is host-published for
every version (base + upgrade) and on-host protocol tests reach 127.0.0.1:64738.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>