Moved the NodeJS version of the application to the app/ directory.

app/frontend/vitest.config.ts

@@ -0,0 +1,8 @@
+import { defineConfig } from "vitest/config";
+
+export default defineConfig({
+  test: {
+    environment: "jsdom",
+    setupFiles: ["./test/setup.ts"]
+  }
+});