Initialize League GUI prototype

vite.config.ts

@@ -0,0 +1,13 @@
+/// <reference types="vitest" />
+
+import react from "@vitejs/plugin-react";
+import { defineConfig } from "vitest/config";
+
+export default defineConfig({
+  plugins: [react()],
+  test: {
+    environment: "jsdom",
+    globals: true,
+    setupFiles: "./src/test/setup.ts"
+  }
+});