feat(m9/T22): template tree search box (wire TemplateFolderTree.Filter)

src/ZB.MOM.WW.ScadaBridge.CentralUI/Components/Pages/Design/Templates.razor

@@ -79,12 +79,28 @@
             </div>
         </div>
 
-        <div style="max-height: calc(100vh - 160px); overflow-y: auto; padding: 4px;">
+        <div class="mb-3" style="max-width: 320px;">
+            <div class="input-group input-group-sm">
+                <input type="text" class="form-control form-control-sm"
+                       placeholder="Search templates..."
+                       value="@_searchText"
+                       @oninput="e => _searchText = e.Value?.ToString() ?? string.Empty" />
+                @if (!string.IsNullOrEmpty(_searchText))
+                {
+                    <button class="btn btn-outline-secondary" type="button"
+                            title="Clear search"
+                            @onclick="() => _searchText = string.Empty">✕</button>
+                }
+            </div>
+        </div>
+
+        <div style="max-height: calc(100vh - 200px); overflow-y: auto; padding: 4px;">
             <TemplateFolderTree @ref="_tree"
                                 Folders="_folders"
                                 Templates="_templates"
                                 SelectionMode="TreeViewSelectionMode.Single"
                                 ExtraTemplateChildren="BuildCompositionLeavesFor"
+                                Filter="@_searchText"
                                 StorageKey="templates-tree">
                 <NodeContent Context="node">
                     @RenderNodeLabel(node)
@@ -109,6 +125,10 @@
     private List<Template> _templates = new();
     private List<TemplateFolder> _folders = new();
 
+    // Search text bound to the filter input; passed as Filter to TemplateFolderTree
+    // which handles substring matching and ancestor auto-expand internally.
+    private string _searchText = string.Empty;
+
     private bool _loading = true;
     private string? _errorMessage;