fix：修改由预览返回index页时selections.mode属性错误的bug

src/views/Index.vue

@@ -23,7 +23,11 @@ import PenProps from './components/PenProps.vue';
 import PensProps from './components/PensProps.vue';
 
 import { useSelection, SelectionMode } from '@/services/selections';
+import {onMounted} from "vue";
 
+onMounted(()=>{
+  selections.mode = SelectionMode.File
+})
 const { selections } = useSelection();
 </script>