fix: layer panel collapsible tree + element actions (visibility toggle, delete) + RenderEngine skips invisible elements

frontend/src/App.tsx

@@ -331,6 +331,20 @@ const CADEditor: React.FC<CADEditorProps> = ({ projectId, token, onNavigateBack
     }
   }, [layers, blocks, groups, bgConfig, syncHistory, drawingId, token, collab, activeLayerId]);
 
+  const handleToggleElementVisible = useCallback((id: string) => {
+    setElements((prev) => prev.map((e) => {
+      if (e.id === id) {
+        const newEl = { ...e, properties: { ...e.properties, visible: e.properties?.visible === false ? true : false } };
+        if (token) {
+          setSavedStatus("Speichert…");
+          updateElement(token, newEl.id, newEl).then(() => setSavedStatus("gespeichert")).catch(() => setSavedStatus("Fehler"));
+        }
+        return newEl;
+      }
+      return e;
+    }));
+  }, [token]);
+
   const handleElementsDeleted = useCallback((ids: string[]) => {
     setElements((prev) => {
       const newElements = prev.filter((e) => !ids.includes(e.id));
@@ -980,6 +994,8 @@ const CADEditor: React.FC<CADEditorProps> = ({ projectId, token, onNavigateBack
           onRenameLayer={handleRenameLayer}
           onDuplicateLayer={handleDuplicateLayer}
           onToggleLock={handleToggleLock}
+          onElementsDeleted={handleElementsDeleted}
+          onToggleElementVisible={handleToggleElementVisible}
           elements={elements}
           onRenameBlock={handleRenameBlock}
           onDuplicateBlock={handleDuplicateBlock}