fix: resolve the node the connection landed on, not the first cluster member

_resolve_node() took the first entry of GET /nodes. In a cluster that
lists every member, so a node polled without an explicit `node` driver
argument talked to whichever member came first: pve-dual reported
pve-02's name and VMs, and netOrk's VM sync moved pve-02's VM devices
over to it.

Resolve through GET /cluster/status instead: the entry marked local,
then a match by IP or (short) name, then the sole node of a standalone
host, and otherwise raise rather than guess.

The lookup no longer swallows API errors either. A TLS verification
failure used to leave the IP as the node name, so open() succeeded and
every getter failed quietly while the poll reported success with empty
data. It now surfaces as a ConnectionException from open().

Refs NetOrk/netork#417, NetOrk/netork#418

tests/conftest.py

@@ -138,6 +138,7 @@ def _build_mock_api(
     pve_users=None,
     exec_return="",
     sensors=None,
+    cluster_status=None,
 ):
     """Build a MagicMock ProxmoxAPI with pre-configured return values."""
     api = MagicMock()
@@ -165,6 +166,7 @@ def _build_mock_api(
     # SDN
     cluster = MagicMock()
     api.cluster = cluster
+    cluster.status.get.return_value = cluster_status or []
     cluster.sdn.zones.get.return_value = sdn_zones or SDN_ZONES
     cluster.sdn.vnets.get.return_value = sdn_vnets or SDN_VNETS