Add a job compose file for the test stack and extend the k8s deploy
test to verify new features:
- Namespace isolation: pod exists in laconic-{id}, not default
- Stack labels: app.kubernetes.io/stack label set on pods
- Job completion: test-job runs to completion (status.succeeded=1)
- Secrets: spec secrets: key results in envFrom secretRef on pod
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>