Add folder game, file browser UI, and automated tests.

Introduces a localStorage-backed messy-desktop challenge with sub-steps,
drag-and-drop and Places/Back navigation, IBM Plex Mono, and a /api/health
endpoint. Adds Vitest coverage for the API and level logic plus Playwright
smoke tests.

Made-with: Cursor

tests/api/health-route.test.ts

@@ -0,0 +1,11 @@
+import { describe, expect, it } from "vitest";
+
+import { GET } from "~/app/api/health/route";
+
+describe("GET /api/health", () => {
+  it("returns 200 and status ok", async () => {
+    const res = await GET();
+    expect(res.status).toBe(200);
+    await expect(res.json()).resolves.toEqual({ status: "ok" });
+  });
+});

tests/api/post-hello.test.ts

@@ -0,0 +1,21 @@
+import { describe, expect, it, vi } from "vitest";
+
+vi.mock("~/server/auth", () => ({
+  auth: vi.fn(async () => null),
+}));
+
+vi.mock("~/server/db", () => ({
+  db: {},
+}));
+
+import { createCaller } from "~/server/api/root";
+import { createTRPCContext } from "~/server/api/trpc";
+
+describe("tRPC post.hello", () => {
+  it("returns a greeting for the given text", async () => {
+    const ctx = await createTRPCContext({ headers: new Headers() });
+    const caller = createCaller(ctx);
+    const out = await caller.post.hello({ text: "Tester" });
+    expect(out.greeting).toBe("Hello Tester");
+  });
+});