feat: implement the HypervisorDriver VM contract

start_vm, stop_vm, reboot_vm, suspend_vm and get_vm_config existed only
as declarations. netOrk called Proxmox's own power_vm and read a VM's
raw config through _node_api(), so no other hypervisor could serve the
same endpoints. These let netOrk talk to every hypervisor alike.

The power methods accept a VM's name or vmid, wait for the Proxmox task,
and raise ValueError/RuntimeError as the contract says instead of
returning a result dict. A forced reboot of a container is stop + start,
since LXC has no reset; suspending a container is refused. power_vm is
unchanged for existing callers.

get_vm_config moves the config parsing netOrk did in
_parse_proxmox_hw_config into the driver and returns a VMConfigDict:
disks with storage and size, NICs with model, MAC, bridge and VLAN, CPU
topology, firmware, machine type and PCI/USB passthrough.

get_vms reports vmid as a string ("100"), following
napalm-device-types 2.0, still ordered numerically.

napalm_proxmox/vm_mixin.py

@@ -216,7 +216,7 @@ class ProxmoxVMMixin:
         """Return all VMs (QEMU) and containers (LXC) on this node.
 
         Each entry contains:
-        * vmid (int)        - Proxmox VM/container ID
+        * vmid (str)        - Proxmox VM/container ID, e.g. ``"100"``
         * name (str)        - display name
         * type (str)        - ``"vm"`` or ``"container"``
         * status (str)      - ``"running"``, ``"stopped"``, etc.
@@ -257,7 +257,7 @@ class ProxmoxVMMixin:
 
                 disks, onboot = self._get_vm_disk_and_boot(vmid, "qemu")
                 result.append({
-                    "vmid": vmid,
+                    "vmid": str(vmid),
                     "name": name,
                     "type": "vm",
                     "status": status,
@@ -301,7 +301,7 @@ class ProxmoxVMMixin:
 
                 disks, onboot = self._get_vm_disk_and_boot(vmid, "lxc")
                 result.append({
-                    "vmid": vmid,
+                    "vmid": str(vmid),
                     "name": name,
                     "type": "container",
                     "status": status,
@@ -321,7 +321,7 @@ class ProxmoxVMMixin:
         except Exception as exc:
             logger.warning("get_vms: failed to list LXC containers: %s", exc)
 
-        return sorted(result, key=lambda x: x["vmid"])
+        return sorted(result, key=lambda x: int(x["vmid"]))
 
     # Disk-key prefixes for QEMU: scsi, virtio, ide, sata (exclude cdrom/none entries)
     _DISK_KEYS_VM = re.compile(r"^(scsi|virtio|ide|sata)\d+$")