Extracted the heal_podman_state cleanup list as a module-level
HEAL_RUNTIME_SUBDIRS const so a unit test can structurally enforce
the invariant: the list must contain "containers" + "libpod" but
must NOT contain "podman" (which holds systemd's podman.sock
listener and was the bug fixed in commit bb421803).
If anyone re-adds "podman" — accidentally, by reverting, or by
copy-paste from old plan memory — this test fires before we ship,
not on the next deploy when it nukes the orchestrator's HTTP path.
Total tests: 614 → 615.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>