System Prompt Customization for Personalization & Select and Copy

Feature Description

Add a /personalization (or /persona) command where it's a input box for a custom instructions for the model you use. Could be Project or Global personalization. For example you could ask it to add some emojis or a header so that the AI's response would be more reactive, or to never use an explanation inside the code the AI is writing

And then in OpenCode, when you select a text, it automatically gets copied to your clipboard, works for Linux/MacOS and Windows. Or Claude Code-like, you could select the text and Ctrl+Shift+C to copy.

Use Case

This would be beneficial because, especially for younger developers including me, they do not like bland AI responses, like a cold, emojiless response. And would like the copy mechanism as it is useful to share plans or something else without sharing the whole entire chat.

Additional Context

No response

How important is this to you?

Nice to have

该 issue 未列出任何文件、测试或入口点。首先梳理涉及的命令处理和终端接口，然后明确个性化与复制行为是否是相互独立的交付内容；完成定义应明确项目/全局范围，以及在 Linux、macOS 和 Windows 上的预期行为。