e8ac99174a
M78 step 1. The bundled maintenance/docker_prune.yml was a single
`docker system prune -f`; the upcoming per-host prune buttons need a
granular split. Add a `prune_target` extra-var:
- containers → docker container prune -f
- images → docker image prune -f (+ -a when prune_all_images)
- system → docker system prune -f (+ -a / --volumes) — the DEFAULT,
so existing manual/scheduled callers (which set no var)
keep today's behavior.
Reuses the existing bundled playbook rather than adding parallel files;
keeps the description/category/confirm meta so it still self-describes as
a confirm-gated maintenance run. Adds unit coverage: the playbook stays
valid YAML, its meta still discovers, and all three targets are guarded.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CAGR73DUowdVFVvYzLXC5C