Running tests_integration against rootless Podman surfaced three issues; none
affect the Docker/CI path:
- run.py: add a SPOOLMAN_CONTAINER_ENGINE env var (defaults to "docker") so the
build/compose commands can be driven by podman instead.
- Dockerfile: drop `--chown=app:app` from the builder-stage COPYs. The "app"
user only exists in the runner stage; Docker/BuildKit tolerated the dangling
reference but Podman rejects it. Final ownership is unchanged — it is set when
the files are copied into the runner stage.
- docker-compose-postgres.yml: add a pg_isready healthcheck and gate spoolman on
`condition: service_healthy`, matching the mariadb/cockroachdb compose files.
Without it spoolman raced postgres' initdb and died on connection-refused
before running migrations.
Verified: full 4-DB suite (sqlite/postgres/mariadb/cockroachdb) green via
`SPOOLMAN_CONTAINER_ENGINE=podman uv run poe itest` — 223 tests each.
Donkie