fix : add missing test

tests/public-performance.test.ts

@@ -1,6 +1,10 @@
 import { readFile } from "node:fs/promises";
 
-import { describe, expect, it } from "vitest";
+import { describe, expect, it, vi } from "vitest";
+
+vi.hoisted(() => {
+  vi.stubEnv("BASE_URL", "https://guide.example.test");
+});
 
 import robots from "@/app/robots";