refactor: replace svelte.config.js with svelte.config.ts to eliminate untyped code

svelte.config.ts

@@ -1,13 +1,11 @@
+import type { Config } from "@sveltejs/kit";
+
 import adapter from "@sveltejs/adapter-static";
 import { vitePreprocess } from "@sveltejs/vite-plugin-svelte";
 
-/** @type {import("@sveltejs/kit").Config} */
-const config = {
+export default {
 	preprocess: vitePreprocess(),
-
 	kit: {
 		adapter: adapter(),
 	},
-};
-
-export default config;
+} satisfies Config;