feat(proxmox): per-node CPU type based on hardware capabilities

Add proxmox_node_cpu map — aya01 (Celeron N5105, no AVX2) stays at
x86-64-v2-AES; inko01/lulu/mii01/naruto01 (all AVX2-capable) use x86-64-v3.
Task looks up cpu type by vm.node with x86-64-v2-AES as fallback.

roles/proxmox/tasks/55_create_vm.yaml

@@ -18,7 +18,7 @@
     tags: "{{ proxmox_tags }}"
     description: "Created via Ansible with cloud-init"
     boot: "order=scsi0"
-    cpu: "x86-64-v3"
+    cpu: "{{ proxmox_node_cpu[vm.node] | default('x86-64-v2-AES') }}"
     ciuser: "{{ vm.ciuser }}"
     cipassword: "{{ vm_secrets[proxmox_secrets_prefix + '_' + vm.name.replace('-', '_')] }}"
     ipconfig: