docs: Add FPM bilingual documentation module

[Fuyeors]

Summary

• Add a bilingual FPM documentation module for ordinary users and developers.
• Organize content into overview, tutorial, how-to, and CLI reference sections.
• Register the module in both English and Simplified Chinese indexes.

Documentation structure

• content/fpm/overview
• content/fpm/tutorials/getting-started
• content/fpm/how-to/publish
• content/fpm/reference/cli

The content follows task-oriented navigation patterns informed by Microsoft Learn and the Diátaxis documentation model.

Commit identity

Manus AI bot+manus@fuyeor.com