refactor(uns): drop dead LoadEquipmentChildrenAsync + LinesForCluster; fix stale comment

src/Server/ZB.MOM.WW.OtOpcUa.AdminUI/Components/Pages/Uns/GlobalUns.razor

@@ -151,18 +151,6 @@
             .Select(a => (a.EntityId!, a.DisplayName))
             .ToList();
 
-    /// <summary>Returns the <c>(Id, Display)</c> line options inside a single cluster, for the equipment picker.</summary>
-    private IReadOnlyList<(string Id, string Display)> LinesForCluster(string? clusterId) =>
-        _roots
-            .SelectMany(ent => ent.Children)
-            .Where(c => c.Kind == UnsNodeKind.Cluster && c.ClusterId == clusterId)
-            .SelectMany(c => c.Children)
-            .Where(a => a.Kind == UnsNodeKind.Area)
-            .SelectMany(a => a.Children)
-            .Where(l => l.Kind == UnsNodeKind.Line && l.EntityId is not null)
-            .Select(l => (l.EntityId!, l.DisplayName))
-            .ToList();
-
     /// <summary>
     /// Toggles a structural node's expansion. Equipment nodes are leaves (no expander),
     /// so this path only ever fires for Enterprise/Cluster/Area/Line.
@@ -370,8 +358,8 @@
     }
 
     /// <summary>
-    /// Expands every structural node (Enterprise/Cluster/Area/Line). Equipment nodes
-    /// are intentionally left collapsed because expanding them would trigger lazy loads.
+    /// Expands every structural container node (Enterprise/Cluster/Area/Line) in the tree.
+    /// Equipment is a leaf node and has no expansion; <see cref="ExpandStructural"/> skips it.
     /// </summary>
     private void ExpandAll()
     {