feat: 品牌替换 + 启动优化 + AGENTS.md 模板定制

- 品牌替换：OpenCode/opencode → AirCoding/aircoding（16+ 文件）
- Logo ASCII art：修复 left/right 行数不匹配导致的启动崩溃
- 启动诊断：添加 OPENCODE_PRINT_TIMING 计时探针
- dev 模式默认 --pure 跳过外部插件加载
- AGENTS.md 模板：追加 AirCoding 多 Agent 专项段落
- architect prompt + plugin：强化 AGENTS.md 产出验证

packages/docs/essentials/images.mdx

@@ -0,0 +1,56 @@
+---
+title: "Images and embeds"
+description: "Add image, video, and other HTML elements"
+icon: "image"
+---
+
+<img style={{ borderRadius: "0.5rem" }} src="https://mintlify-assets.b-cdn.net/bigbend.jpg" />
+
+## Image
+
+### Using Markdown
+
+The [markdown syntax](https://www.markdownguide.org/basic-syntax/#images) lets you add images using the following code
+
+```md
+![title](/path/image.jpg)
+```
+
+Note that the image file size must be less than 5MB. Otherwise, we recommend hosting on a service like [Cloudinary](https://cloudinary.com/) or [S3](https://aws.amazon.com/s3/). You can then use that URL and embed.
+
+### Using embeds
+
+To get more customizability with images, you can also use [embeds](/writing-content/embed) to add images
+
+```html
+<img height="200" src="/path/image.jpg" />
+```
+
+## Embeds and HTML elements
+
+<iframe
+  width="560"
+  height="315"
+  src="https://www.youtube.com/embed/4KzFe50RQkQ"
+  title="YouTube video player"
+  frameBorder="0"
+  allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture"
+  allowFullScreen
+  style={{ width: "100%", borderRadius: "0.5rem" }}
+></iframe>
+
+<br />
+
+<Tip>
+
+Mintlify supports [HTML tags in Markdown](https://www.markdownguide.org/basic-syntax/#html). This is helpful if you prefer HTML tags to Markdown syntax, and lets you create documentation with infinite flexibility.
+
+</Tip>
+
+### iFrames
+
+Loads another HTML page within the document. Most commonly used for embedding videos.
+
+```html
+<iframe src="https://www.youtube.com/embed/4KzFe50RQkQ"> </iframe>
+```