Remove duplicate YouTube covers from README demo sections

README.md

@@ -31,8 +31,6 @@
 
 https://github.com/user-attachments/assets/3acfecf4-bf48-4c76-8245-2eeef0dedb1f
 
-[![Android Quick Test cover showing a real device browser and FSQ execution evidence](docs/media/quick-test-poster.png)](https://youtu.be/f1sobvVHNg0)
-
 [Watch on YouTube](https://youtu.be/f1sobvVHNg0) · [English captions](docs/media/quick-test.en.srt) · [Media sources and review status](docs/media/quick-test-demo-provenance.md)
 
 The video shows one real Android Quick Test: find the FSQ repository, follow its About website link, and verify both homepage headlines. You can start with Web; platform setup and execution differ, and search results and outcomes can vary.

README.zh-CN.md

@@ -31,8 +31,6 @@
 
 https://github.com/user-attachments/assets/3acfecf4-bf48-4c76-8245-2eeef0dedb1f
 
-[![Android Quick Test 演示封面：真实设备浏览器和 FSQ 执行证据](docs/media/quick-test-poster.png)](https://youtu.be/f1sobvVHNg0)
-
 [在 YouTube 观看](https://youtu.be/f1sobvVHNg0) · [英文字幕](docs/media/quick-test.en.srt) · [媒体来源与审查状态](docs/media/quick-test-demo-provenance.md)
 
 视频展示 Android 上的一次真实 Quick Test：搜索 FSQ 仓库，沿 About 官网链接访问主页，验证两句主标题。你可以先使用 Web 试用；不同平台的环境和执行过程不同，搜索结果和测试结果也可能变化。

docs/media/README.md

@@ -14,7 +14,7 @@ The current promotional demonstration is **Android Quick Test**: find the FSQ-la
 - [Observed acceptance and pending verification](media-acceptance.md)
 - [Current sequence](demo-storyboard.md)
 
-The READMEs link the GitHub attachment and matching cover; the Website and [standalone demo](../demo.html) activate native playback only on a click. Both retain explicit GitHub and YouTube viewing links. The Website bundles captions and images on the Pages origin. No large video is committed.
+The READMEs embed the GitHub attachment and retain textual YouTube, caption, and provenance links; the Website and [standalone demo](../demo.html) activate native playback only on a click. Both retain explicit GitHub and YouTube viewing links. The Website bundles captions and images on the Pages origin. No large video is committed.
 
 The share image `../assets/social-preview.png` uses the same white/green identity and the headline “Describe a goal. Test the real app.”. Its byte-identical Website publication copy is `frontend/website/public/social-preview.png`; the stable social metadata URL is `https://fsq-lab.github.io/FSQ/social-preview.png`.
 

tests/test_distribution_contract.py

@@ -303,12 +303,18 @@ def _markdown_section(document: str, heading: str) -> str:
 def test_readmes_share_current_media_and_resolvable_local_destinations() -> None:
     current_video = "https://github.com/user-attachments/assets/3acfecf4-bf48-4c76-8245-2eeef0dedb1f"
     current_youtube = "https://youtu.be/f1sobvVHNg0"
-    expected_images = {f"docs/media/quick-test-{name}.png" for name in ("poster", "task", "execution", "result")}
+    expected_images = {f"docs/media/quick-test-{name}.png" for name in ("task", "execution", "result")}
     for name in ("README.md", "README.zh-CN.md"):
         path = ROOT / name
         readme = path.read_text(encoding="utf-8")
         assert current_video in readme
         assert current_youtube in readme
+        demo_heading = "## See a complete test" if name == "README.md" else "## 看一次完整测试"
+        demo = _markdown_section(readme, demo_heading)
+        assert demo.splitlines().count(current_video) == 1
+        assert re.search(rf"(?<!!)\[[^\]\n]+\]\({re.escape(current_youtube)}\)", demo)
+        assert "![" not in demo
+        assert "<img" not in demo.lower()
         assert "aa9d0a12-2f93-4894-8349-52a013424939" not in readme
         assert "QqCahxGDdS0" not in readme
         images = re.findall(r"!\[([^\]]+)\]\((docs/media/[^)]+)\)", readme)