单分格时，自动选择第一个

src/pages/view/components/ViewerContainer.tsx

@@ -484,6 +484,8 @@ const ViewerContainer: React.FC<ViewerContainerProps> = ({ imageUrls }) => {
     console.log('Rendering  layout', gridLayout);
     switch (gridLayout) {
       case '1x1': {
+        //变成单分格时，自动选中第一个
+        dispatch(toggleViewerSelection(allViewerUrls[0]));
           return (
             <div
               className="h-full w-full"