FIXED - build type errors (vitest fileParallelism placement, NODE_ENV assignment)

tests/middleware.test.ts

@@ -39,7 +39,7 @@ function createMockRequest(url: string) {
 describe("middleware locale runtime config", () => {
   beforeEach(() => {
     vi.resetModules();
-    process.env.NODE_ENV = "production";
+    vi.stubEnv("NODE_ENV", "production");
     delete process.env.SITE_RUNTIME_ORIGIN;
     createMiddlewareMock.mockReset();
     intlHandlerMock.mockReset();
@@ -49,6 +49,7 @@ describe("middleware locale runtime config", () => {
 
   afterEach(() => {
     vi.unstubAllGlobals();
+    vi.unstubAllEnvs();
   });
 
   it("passes the runtime default locale into next-intl middleware", async () => {