fix(uns): re-entrancy guard + clear stale error + PageTitle on GlobalUns (review)

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

@@ -5,6 +5,8 @@
 @using ZB.MOM.WW.OtOpcUa.AdminUI.Components.Shared.Uns
 @inject IUnsTreeService Svc
 
+<PageTitle>UNS</PageTitle>
+
 <div class="d-flex justify-content-between align-items-center mb-3">
     <h4 class="mb-0">UNS</h4>
     <span class="text-muted small">Changes apply on the next deployment.</span>
@@ -58,10 +60,13 @@
     /// </summary>
     private async Task ToggleAsync(UnsNode node)
     {
+        if (node.Loading) return;
+
         node.Expanded = !node.Expanded;
 
         if (node.Kind == UnsNodeKind.Equipment && node.Expanded && !node.Loaded)
         {
+            node.Error = null;
             node.Loading = true;
             StateHasChanged();
             try