feat(provisioning): implement VM provisioning mixin for Proxmox

Add ProxmoxVMProvisionMixin with three methods:
- create_vm_from_cloud_init(): clone template → dual-NIC config → Cloud-Init → start
- destroy_vm(): stop → delete VM → cleanup snippets
- get_vm_status(): poll guest-agent for IP with optional wait-for-IP polling

Tests (9 cases):
- _wait_for_task success/error/timeout handling
- create_vm happy path + missing snippet storage error
- get_vm_status with/without wait-for-IP, timeout handling
- destroy_vm on running or already-stopped VM

All tests pass (100% coverage on mixin code paths).

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

napalm_proxmox/driver.py

@@ -49,6 +49,7 @@ from napalm_proxmox.sdn_mixin import ProxmoxSDNMixin
 from napalm_proxmox.lldp_mixin import ProxmoxLLDPMixin
 from napalm_proxmox.config_mixin import ProxmoxConfigMixin
 from napalm_proxmox.vm_mixin import ProxmoxVMMixin
+from napalm_proxmox.vm_provision_mixin import ProxmoxVMProvisionMixin
 from napalm_proxmox.routing_mixin import ProxmoxRoutingMixin
 from napalm_proxmox.system_mixin import ProxmoxSystemMixin
 
@@ -68,6 +69,7 @@ class ProxmoxDriver(
     ProxmoxLLDPMixin,
     ProxmoxConfigMixin,
     ProxmoxVMMixin,
+    ProxmoxVMProvisionMixin,
     ProxmoxRoutingMixin,
     ProxmoxSystemMixin,
     HypervisorDriver,