fix: import

Author: lilrosalyn

svelte.config.js

@@ -1,6 +1,7 @@
 import { mdsvex } from "mdsvex";
 import adapter from "@sveltejs/adapter-static";
 import { vitePreprocess } from "@sveltejs/vite-plugin-svelte";
+import { dev } from "$app/environment";
 
 /** @type {import("@sveltejs/kit").Config} */
 const config = {