[Bug]: 今日头条发布失败，页面提示：第1张图片URI异常，请重新上传

### Description / 问题描述

使用https://md.doocs.org/编辑器，内容中插入图片，发布到【今日头条】页面提示：第1张图片URI异常，请重新上传

### Steps to Reproduce / 复现步骤

使用https://md.doocs.org/编辑器，内容中插入图片。
使用插件发布到【今日头条】

### Expected Behavior / 预期行为

正常发布

### Suggested Implementation / 实现建议

_No response_

### Platform / 平台

今日头条

### Browser / 浏览器

Chrome

### Extension Version / 扩展版本

1.3.6

### Environment Details / 环境信息

_No response_

### Screenshots / 截图

_No response_

### Additional Context / 补充信息

_No response_

Reproduce the failure in the Chrome extension using md.doocs.org, an inserted image, and the 今日头条 publishing flow described in the issue. Start by tracing how the extension handles the first image URI in version 1.3.6 and compare the result with the platform's expected image input. Done means an article containing an image publishes successfully to 今日头条.

Written by the indexing model from the issue text.