chore: pins vitest-cucumber to exact version

Author: wgordon17

package.json

@@ -30,7 +30,7 @@
     "zod": "4.3.6"
   },
   "devDependencies": {
-    "@amiceli/vitest-cucumber": "^6.3.0",
+    "@amiceli/vitest-cucumber": "6.3.0",
     "@cloudflare/vite-plugin": "1.30.1",
     "@cloudflare/vitest-pool-workers": "0.13.4",
     "@playwright/test": "1.58.2",