docs: add Simplified Chinese README

[18166714330cl-maker]

Summary

• Add a Simplified Chinese README as a localized entry point for PicoClaw users.
• Link the English README to the new Chinese version.
• Cover setup, providers, channels, tools, Gene Evolution, Edge Server, skills, CLI, hardware targets, ecosystem, contributing, and troubleshooting.

Testing

• Documentation-only change.
• Verified referenced local links in README.zh-CN.md exist in the repository.

Bounty

Intended for the Chinese documentation translation bounty on the Clawland bounty board.

[18166714330cl-maker]

Thanks for taking a look.

I treated this as a localized documentation entry point rather than a broad rewrite of the English README.

The issue I’m addressing is that Chinese users need a complete first-pass guide that preserves the project’s structure and links back into the existing docs. The PR adds that entry point while keeping the English README as the canonical source.

What changed:

• Added README.zh-CN.md covering setup, providers, channels, tools, Gene Evolution, Edge Server, skills, CLI, hardware targets, ecosystem, contributing, and troubleshooting.
• Added a language switch link from the English README.
• Kept local links aligned with existing repository paths.

Verification:

• Documentation-only change.
• Checked referenced local links in the Chinese README exist in the repository.

The main risk is wording consistency with the project’s preferred terminology. If the direction is right, I can revise terminology or section order to match your convention.