KC_DB was set to dev-mem (H2 in-memory) — every time the keycloak
container went idle or restarted, the realm + the M7.1 test users
dissolved and the next smoke run failed with token_not_found until
realm-export was re-imported manually. Bit twice during the M7.1
testing session.
dev-file points H2 at /opt/keycloak/data/h2/ and the new
keycloak-data named volume keeps it across container lifecycles. The
realm-export.json bind-mount is still read-only and re-imported on
fresh starts via `--import-realm`, so a `docker compose down -v` is
still the canonical "rebuild from scratch" lever.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>