开放的侧边栏底座，支持三方拓展注册新侧边栏页面。内置文件渲染编辑/终端/侧边对话/Git/子代理页面 ｜ Open sidebar foundation, supports third-party extensions to register new sidebar pages. Built-in file rendering/editing, terminal, side chat, Git, and sub-agent pages.

Follow the tangent. Keep the thread. Annotate, explore on the side, and bring answers back to DeepSeek Harness. / 思路可以分岔，主线始终向前。划选注释、侧边追问，再把结论带回正在推进的任务。