docs: add Chinese (zh-CN) README translation

[isagoakira]

📖 中文 README 翻译

此 PR 为 addyosmani/agent-skills 添加了中文 README (README.zh-CN.md)。

由 Readme Translator 自动生成 🤖

[incrediblemohnish5]

I really support such initiatives

[federicobartoli]

Thanks for taking the time to translate! A few procedural concerns before this can move forward:

1. Overlap with docs: add Chinese translations for all skills and project docs #120: that PR adds Chinese translations for the README and all skills (+6501 lines). Adding a separate README.zh-CN.md here would either duplicate or diverge from docs: add Chinese translations for all skills and project docs #120's work. Worth coordinating with that author.
2. Auto-generated content: the PR description notes this was produced by an automated "Readme Translator". For a public-facing doc, a native-speaker pass would help catch any terms-of-art or tone issues — bot-translated technical content tends to drift on the nuances.
3. Translation policy: this would be the first non-English README in the repo. Worth a maintainer call on whether the project wants to commit to maintaining translations (every README update requires re-translation), or if a single English README + a community-translations note is the lower-maintenance path.

No objection to the work itself — just want to make sure the maintainer signs off on the broader policy before merging.