fix(zigbee): hide check method in modal, force none/online for zigbee nodes

Zigbee nodes have no IP-based check — hide Check Method and Check Target
fields in NodeModal for all three zigbee types. Default and force
check_method='none' so the scheduler marks them always online.
Backend approve and zigbee import routes also set status='online' and
check_method='none' for zigbee node types.

backend/app/api/routes/zigbee.py

@@ -157,7 +157,8 @@ async def _persist_pending_import(
             node = Node(
                 label=label,
                 type=n.get("type") or "zigbee_coordinator",
-                status="unknown",
+                status="online",
+                check_method="none",
                 ieee_address=ieee,
                 services=[],
             )