Chinese translation of the Sigil User Guide — first release (Sigil 用户指南 中文版)

[cndxflwb]

Hi all,

I would like to share a complete Simplified Chinese translation of the Sigil User Guide.

What it is
- A full Chinese translation of the user guide, targeting Sigil 2.6.2 and later.
- Based on the official guide project (baseline commit a9c5370). Text only — no changes
to the document structure or the styling.

Where to get it
- Download (epub): https://github.com/cndxflwb/sigil-us...zh-CN/releases
- Source (branch zh-CN, README in Chinese): https://github.com/cndxflwb/sigil-user-guide-zh-CN
- Upstream project: https://github.com/Sigil-Ebook/sigil-user-guide

Feedback
- Corrections and suggestions are very welcome - please open an issue or a pull request
on the GitHub repository.
- The "read online" link in the README points to the official English version at
sigil-ebook.com; there is no Chinese online version yet, so the epub is the way to read it.

A small note for the maintainers
- .github/workflows/build_guide.py produces a non-compliant archive when it is run on
Windows: the entry names are written with backslashes (OEBPS\Text\...) because
ZipFile.write() receives an os.path.join() path, and OCF requires forward slashes.
CI runs on ubuntu-latest so it never shows up there, but it does break local Windows
builds. Normalizing the archive name (e.g. .replace(os.sep, '/')) fixes it. Happy to
send a PR if that is useful.

Thanks to the Sigil developers and to everyone who maintains the user guide.

[icearch]

非常好项目，使我大拇指旋转。

最开头的robustness是不是翻译成稳健性更好？