Document plugin-first packaging (manifest, commands, skills, hooks) and
have install.sh build the CLI, install the tmux dashboard, and register
the plugin so clone-and-setup matches how the project is shipped.
Restructure docs so README.md is full Chinese documentation with TOC.
English content moves to README.en.md; drop README.zh-CN.md. Align
CONTRIBUTING, install script, package/plugin descriptions, and skill links.
Redredchen01