edit-config.yml was never included by the role, so lxc_id_mappings and GPU
passthrough were silently ignored. It also used blockinfile, whose comment
markers are incompatible with Proxmox hoisting all comments to the top of the
.conf on every write -- which orphans the markers and empties the managed block.
Rewrite edit-config.yml to manage raw lxc.* lines with lineinfile (keyed on each
exact line, churn-free, immune to comment hoisting), delegated to the Proxmox
host. Include it from main.yml after clone/create but before start.yml, while the
container is stopped, since ID mappings can't change on a running container.
patrick