test: replace flaky login assertions with localStorage JWT check

loginAndGetJwt / loginAsStudent no longer wait 120s for text patterns
that may not appear. Instead they wait for Authorization in localStorage,
which is faster and more reliable.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

tests/course-package.spec.ts

@@ -48,9 +48,11 @@ async function loginAndGetJwt(page: any): Promise<string> {
   ) {
     await page.locator('.van-grid-item').first().click();
   }
-  await expect(
-    page.getByText(/请选择您的登录身份|欢迎回来|进入工作台/),
-  ).toBeVisible({ timeout: 120_000 });
+  // Wait for JWT to appear in localStorage (login completed)
+  await page.waitForFunction(
+    () => !!window.localStorage.getItem('Authorization'),
+    { timeout: 90_000 },
+  );
 
   if (
     await page.getByText('请返回微信小程序完成登录').isVisible().catch(() => false)