The prune step called bare 'ctr', which has never existed as a
standalone binary on these k3s nodes - only the k3s binary itself
(bundling 'k3s ctr'/'k3s crictl' subcommands) lives at
/usr/local/bin. The failure was silently swallowed by '|| true',
so the CronJob has been reporting Complete every 10 minutes for
68 days while doing nothing; node disk sat at 83% used.
Verified live: patched the CronJob's command to invoke
/usr/local/bin/k3s ctr directly, manually triggered a run, confirmed
it actually prunes now (deleted ~75 dangling images).
This CronJob and its ServiceAccount previously existed only as a
manually-applied live object, not tracked in git. Adding the
manifests here and wiring them into clusters/production so Flux
manages it going forward instead of it silently drifting again.
