chore: add vitest project config and yarn constraints

packages/booking-flow/package.json

@@ -34,6 +34,6 @@
     "eslint-plugin-import": "^2.31.0",
     "eslint-plugin-simple-import-sort": "^12.1.1",
     "typescript": "5.8.3",
-    "vitest": "^3.2.3"
+    "vitest": "^3.2.4"
   }
 }

packages/booking-flow/vitest.config.ts

@@ -1,7 +1,9 @@
-export default {
+import { defineConfig } from "vitest/config"
+
+export default defineConfig({
   test: {
     globals: true,
     environment: "jsdom",
     setupFiles: ["./vitest-setup.ts"],
   },
-}
+})