md2 v0.2.1: Zhihu image paste fix

md2 v0.2.1: fixes images failing (上传失败) when pasting into the Zhihu editor.

Install the VS Code extension

• Download md2-0.2.1.vsix below, then in VS Code run Extensions: Install from VSIX…, or use code --install-extension md2-0.2.1.vsix.
• Web app: https://brycewang-stanford.github.io/md2/

Fixed

• 知乎 images no longer show 上传失败. Zhihu re-hosts every pasted image by fetching its URL from Zhihu's servers, so local paths and VS Code preview URIs always failed. On copy (VS Code panel, md2 zhihu --copy), local images now become public URLs: jsDelivr links pinned to the pushed commit for files already on GitHub, an image_base front-matter / --image-base prefix for your own host, or inline base64 as a last resort. The Zhihu tab now warns about any image Zhihu can't fetch.

Docs

• README split into English (README.md) and 简体中文 (README.zh-CN.md), for the repo and the VS Code extension.