Add vite preprocessor to allow TypeScript

svelte.config.js

 import adapter from '@sveltejs/adapter-node';
+import { vitePreprocess } from '@sveltejs/kit/vite';
 import { importAssets } from 'svelte-preprocess-import-assets';
 
 /** @type {import('@sveltejs/kit').Config} */
@@ -10,7 +11,8 @@ const config = {
 		}
 	},
 	preprocess: [
-		importAssets()
+		importAssets(),
+		vitePreprocess()
 	]
 };