fix(e2e): Step4标题heading等待超时从默认5s增加到15s，防止预览渲染延迟导致超时

apps/web/e2e/core-generation.spec.ts

@@ -201,7 +201,7 @@ test.describe("Core generation flow", () => {
     await page.getByRole("button", { name: "下一步" }).click()
 
     // Step 4: title
-    await expect(page.getByRole("heading", { name: /选择标题/ })).toBeVisible()
+    await expect(page.getByRole("heading", { name: /选择标题/ })).toBeVisible({ timeout: 15000 })
     const titleText = `E2E Test ${suffix}`
     await page.getByPlaceholder("输入自定义标题…").fill(titleText)
     await page.getByRole("button", { name: "下一步" }).click()
@@ -297,3 +297,4 @@ test.describe("Core generation flow", () => {
     expect(Array.isArray(tasksData.items)).toBe(true)
   })
 })
+