修正启动检查系统变体用例的负向断言竞态

- 先等系统变体经 unhandledrejection 抛出（并校验抛出物带 Rust 原文），再断言登录页没有该文案
- 原写法在首个 waitFor tick 就因 queryByText 返回 null 而通过，没真正验证拒绝落地后的文案

apps/ai-game-creator-shell/tests/appSurface/auth.suite.ts

@@ -271,6 +271,11 @@ export function registerAuthTests() {
 
   it('keeps transport details out of the login copy by throwing system variants through', async () => {
     const uninstall = installUnhandledRejectionBridge();
+    const reasons: unknown[] = [];
+    const onRejection = (event: Event) => {
+      reasons.push((event as Event & { reason?: unknown }).reason);
+    };
+    window.addEventListener('unhandledrejection', onRejection);
     try {
       const invoke = vi.fn(async (command: string) => {
         if (command === 'read_client_auth_state') {
@@ -287,12 +292,16 @@ export function registerAuthTests() {
       renderAuthSurface(invoke);
       await loginWithCode();
 
-      await waitFor(() =>
-        expect(screen.queryByText(/无法连接登录服务/u)).toBeNull(),
-      );
+      // 先等系统变体真的经 unhandledrejection 抛出，再断言它没落到登录页文案。
+      await waitFor(() => expect(reasons).toHaveLength(1));
+      expect(reasons[0]).toMatchObject({
+        message: '无法连接登录服务，请确认配套后端或 API 代理已启动后重试',
+      });
+      expect(screen.queryByText(/无法连接登录服务/u)).toBeNull();
       expect(document.body.textContent).not.toContain('ECONNREFUSED');
       await screen.findByRole('main', { name: '登录' });
     } finally {
+      window.removeEventListener('unhandledrejection', onRejection);
       uninstall();
     }
   });