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

playwright.config.ts

@@ -0,0 +1,30 @@
+import { defineConfig, devices } from "@playwright/test";
+
+export default defineConfig({
+  testDir: "./e2e",
+  fullyParallel: true,
+  forbidOnly: !!process.env.CI,
+  retries: process.env.CI ? 2 : 0,
+  workers: process.env.CI ? 1 : undefined,
+  reporter: process.env.CI ? "github" : "html",
+  use: {
+    baseURL: "http://127.0.0.1:3000",
+    trace: "on-first-retry",
+  },
+  projects: [{ name: "chromium", use: { ...devices["Desktop Chrome"] } }],
+  webServer: {
+    command: "npm run dev",
+    url: "http://127.0.0.1:3000",
+    reuseExistingServer: !process.env.CI,
+    timeout: 120_000,
+    env: {
+      ...process.env,
+      NODE_ENV: "development",
+      SKIP_ENV_VALIDATION: "1",
+      DATABASE_URL: "file:./prisma/db.sqlite",
+      AUTH_SECRET:
+        process.env.AUTH_SECRET ??
+        "playwright-local-dev-secret-32chars!!",
+    },
+  },
+});