build(frontend): replace create-react-app with vite (#272)

frontend/tests/setup.js

@@ -0,0 +1,11 @@
+import { expect, afterEach } from "vitest";
+import { cleanup } from "@testing-library/react";
+import matchers from "@testing-library/jest-dom/matchers";
+
+// extends Vitest's expect method with methods from react-testing-library
+expect.extend(matchers);
+
+// runs a cleanup after each test case (e.g. clearing jsdom)
+afterEach(() => {
+  cleanup();
+});