feat: NAPALM drivers for VMware ESXi and vCenter

Two drivers from one package, both in the hypervisor role:

- vmware_esxi talks to one host directly: facts, vmnics and vmkernel
  NICs, CDP/LLDP neighbours, sensors, VMs, datastores and port groups.
- vmware_vcenter talks to a vCenter: every VM of every host it manages,
  with the host as the VM's node, plus distributed port groups. It
  reports no interfaces of its own; the hosts' NICs belong to the hosts.

Both implement the HypervisorDriver VM contract: get_vms, get_vm_config,
start/stop/reboot/suspend_vm and the four snapshot methods, and emit raw
device warnings (maintenance mode, disconnected host, config issues,
host managed by a vCenter, free license making the API read-only).

Every read is a PropertyCollector query for the explicit paths in
paths.py, converted by to_plain() into dicts and lists; the parsers
only ever see that. tools/harvest.py dumps exactly those paths to JSON
and tools/sanitize.py scrubs the dump, so a real host can become a test
fixture without code changes. A VM's vmid is its instance UUID, which
survives vMotion and re-registration; a MoRef does not.

Tested against govmomi's vcsim in ESXi and vCenter mode, including real
power and snapshot tasks. Not yet tested against real hardware.

tests/test_vcsim.py

@@ -0,0 +1,105 @@
+"""End-to-end against govmomi's vcsim: real sessions, real tasks, no mocks.
+
+Skipped unless the simulators are running::
+
+    docker run -d --rm -p 127.0.0.1:8989:8989 vmware/vcsim -l 0.0.0.0:8989
+    docker run -d --rm -p 127.0.0.1:8990:8989 vmware/vcsim -esx -l 0.0.0.0:8989
+    VCSIM_VCENTER_PORT=8989 VCSIM_ESXI_PORT=8990 pytest -m vcsim
+
+vcsim accepts any credentials. It is a simulator: this proves the drivers speak
+the vSphere API correctly, not that they understand a particular real host.
+"""
+
+from __future__ import annotations
+
+import os
+
+import pytest
+from napalm.base.exceptions import ConnectionException
+
+from napalm_vmware import VmwareEsxiDriver, VmwareVcenterDriver
+
+pytestmark = pytest.mark.vcsim
+
+
+def _driver(cls, env):
+    port = os.environ.get(env)
+    if not port:
+        pytest.skip(f"{env} not set; vcsim not running")
+    driver = cls("127.0.0.1", "user", "pass", optional_args={"port": port, "verify_ssl": False})
+    driver.open()
+    yield driver
+    driver.close()
+
+
+@pytest.fixture
+def esxi():
+    yield from _driver(VmwareEsxiDriver, "VCSIM_ESXI_PORT")
+
+
+@pytest.fixture
+def vcenter():
+    yield from _driver(VmwareVcenterDriver, "VCSIM_VCENTER_PORT")
+
+
+def test_esxi_reads(esxi):
+    assert esxi.is_alive() == {"is_alive": True}
+    assert esxi.get_facts()["os_version"].startswith("VMware ESXi")
+    assert "vmnic0" in esxi.get_interfaces()
+    assert esxi.get_vms()
+    assert esxi.get_vm_storage_pools()
+    assert esxi.get_virtual_networks()
+    assert "cpu" in esxi.get_environment()
+    assert isinstance(esxi.get_device_warnings(), list)
+    assert isinstance(esxi.get_lldp_neighbors(), dict)
+
+
+def test_vcenter_reads(vcenter):
+    assert vcenter.get_facts()["model"] == "VMware vCenter Server"
+    vms = vcenter.get_vms()
+    assert len({vm["node"] for vm in vms}) > 1
+    assert vcenter.get_vm_config(vms[0]["vmid"])["vmid"] == vms[0]["vmid"]
+
+
+def test_power_cycle(esxi):
+    vm = esxi.get_vms()[0]
+    esxi.stop_vm(vm["vmid"], force=True)
+    assert _status(esxi, vm) == "stopped"
+    with pytest.raises(RuntimeError, match="not running"):
+        esxi.suspend_vm(vm["vmid"])
+    esxi.start_vm(vm["vmid"])
+    assert _status(esxi, vm) == "running"
+    esxi.suspend_vm(vm["vmid"])
+    assert _status(esxi, vm) == "suspended"
+    esxi.start_vm(vm["vmid"])
+    esxi.reboot_vm(vm["vmid"], force=True)
+    assert _status(esxi, vm) == "running"
+
+
+def test_snapshot_lifecycle(vcenter):
+    vm = vcenter.get_vms()[0]
+    vcenter.create_vm_snapshot(vm["vmid"], "netork-test", description="from pytest")
+    try:
+        (snap,) = [s for s in vcenter.get_vm_snapshots(vm["vmid"]) if s["name"] == "netork-test"]
+        assert snap["description"] == "from pytest"
+        with pytest.raises(ValueError, match="already"):
+            vcenter.create_vm_snapshot(vm["vmid"], "netork-test")
+        vcenter.rollback_vm_snapshot(vm["vmid"], "netork-test")
+    finally:
+        vcenter.delete_vm_snapshot(vm["vmid"], "netork-test")
+    assert not [s for s in vcenter.get_vm_snapshots(vm["vmid"]) if s["name"] == "netork-test"]
+
+
+def test_wrong_driver_is_refused():
+    port = os.environ.get("VCSIM_VCENTER_PORT")
+    if not port:
+        pytest.skip("VCSIM_VCENTER_PORT not set")
+    driver = VmwareEsxiDriver(
+        "127.0.0.1", "u", "p", optional_args={"port": port, "verify_ssl": False}
+    )
+    with pytest.raises(ConnectionException, match="vmware_vcenter"):
+        driver.open()
+
+
+def _status(driver, vm):
+    return next(v["status"] for v in driver.get_vms() if v["vmid"] == vm["vmid"])