I — run pre-flights QEMU guest agent before queueing VM execution
classifyAndGate now checks vm: targets for qemu_guest_agent attribute.
If not_running/missing, returns immediate error instead of queuing forever.
II — policy.yaml: documented host-mutation classifier rule
Added comment clarifying that host-level package/kernel mutations
(apt-get install, dpkg, systemctl enable) always classify as
config_mutation and thus need operator approval.
III — health attribute read-only in update_entity_attributes
Strips scheduler-owned keys (health, last_check_at, last_check) from
attribute updates with a clear message directing agents to
get_health_summary / list_checks instead.
IV — Recorded discovered dependency edges
vm:zimaos → depends-on → lxc:nfs-export (NFS /media/library mount)
vm:zimaos → depends-on → host:strong (NFS /media/ludo-library mount)
Also updated the run tool description to mention both guardrails.