Revert "Add oh-my-opencode-slim (#1100)"

This PR was incorrectly merged by AI agent without proper project owner review.

The AI evaluated this as 'ULTRA SAFE' because it only modified README files,
but failed to recognize that adding external fork promotions to the project
README requires explicit project owner approval - not just technical safety.

This reverts commit 912a56db85.

README.zh-cn.md

@@ -39,11 +39,6 @@
 
 > 这是开挂级别的编程——`oh-my-opencode` 实战效果。运行后台智能体，调用专业智能体如 oracle、librarian 和前端工程师。使用精心设计的 LSP/AST 工具、精选的 MCP，以及完整的 Claude Code 兼容层。
 
-> [!TIP]
-> **正在寻找更轻量的版本？**
->
-> 查看 [oh-my-opencode-slim](https://github.com/alvinunreal/oh-my-opencode-slim) - 一个精简的分支，包含核心功能，适合喜欢最小化配置的用户。
-
 # Claude OAuth 访问通知
 
 ## TL;DR