fix(proxmox_lxc_provision): apply idmaps/GPU config via lineinfile, wire into flow

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.

roles/proxmox_lxc_provision/tasks/main.yml

@@ -32,6 +32,15 @@
     file: create.yml
   when: lxc_template is defined and lxc_clone_from is undefined
 
+# Must run while the container is stopped (before start.yml): ID mappings cannot be
+# changed on a running container. Writes /etc/pve/lxc/<vmid>.conf on the Proxmox host.
+- name: Apply raw LXC config (ID mappings, GPU passthrough)
+  ansible.builtin.include_tasks:
+    file: edit-config.yml
+  vars:
+    lxc_vmid: "{{ lxc_result.vmid | default(lxc_vmid) }}"
+  when: lxc_id_mappings is defined or lxc_nvidia_gpu_mount
+
 - name: Start the created container and wait for ssh
   vars:
     lxc_vmid: "{{ lxc_result.vmid }}"