feat(hypervisor): add optional explicit mac to NICConfigDict

Lets a caller pin a NIC's MAC address ahead of VM creation, needed to
create a matching DHCP static reservation before the VM even exists.

napalm_device_types/hypervisor.py

@@ -583,7 +583,9 @@ class HypervisorDriver(DeviceTypeDriver):
             nics (list[NICConfigDict]) - list of network interface configurations.
               First NIC is primary (DHCP by default); subsequent NICs are optional.
               Each entry specifies bridge, optional vlan_tag (access) or trunk_vlan_tags,
-              and dhcp flag.
+              dhcp flag, and an optional explicit mac address (omit to let the
+              hypervisor auto-generate one; needed when a caller must know the
+              MAC ahead of time, e.g. to create a matching DHCP reservation).
             cloud_init_config (dict) - user-data dict (will be rendered to YAML).
               Should include hostname, bootstrap_token, runcmd, and any custom config.
             image_checksum (string | None) - expected checksum of the downloaded

napalm_device_types/models.py

@@ -713,6 +713,7 @@ class NICConfigDict(TypedDict):
     vlan_tag: NotRequired[int | None]  # Access VLAN (None = untagged)
     trunk_vlan_tags: NotRequired[list[int]]  # Trunk VLAN list (alternative to vlan_tag)
     dhcp: NotRequired[bool]  # Enable DHCP (default True for first NIC, False for others)
+    mac: NotRequired[str]  # Explicit MAC address (omit to let the hypervisor auto-generate one)
 
 
 class VMProvisionResultDict(TypedDict):