The label only protects against reclaims that honour it. The runner
hosts also run jobs we do not control: runner-2 has a second act_runner
registered with gitea.egl.lan on the same Docker daemon, and
opencode-devbox's workflows run raw `docker system prune -af` in 7
places. No prune removes an image a running container uses, so the
smoke step now starts a holder (`ci-reclaim-docker.sh hold`: --rm,
--network none, sleep 3600) right after the preflight, and the
always() cleanup step runs `release` (holder + image). Unprotected now:
only the seconds between the build step's load and the holder starting.
Verified on an isolated docker:29-dind: an unlabelled held image survives
raw system prune and image prune -af (control without holder: deleted);
hold fails on a missing image; holder is AutoRemove + network none;
release removes holder and image; reclaim behaviour unchanged.
joakimp
779efbf4fe