fix: css backgroundurl is undefined

vue.config.js

@@ -16,6 +16,7 @@ module.exports = defineConfig({
   transpileDependencies: true,
   pluginOptions: {
     electronBuilder: {
+      customFileProtocol: "./",
       builderOptions: {
         productName: "江苏省文旅厅",
         asar: false,