[Feature Request] Add /copy command to copy the current assistant response

Problem

Currently, there is no built-in way to copy the current assistant response from a Kimi Code CLI session. Users who want to save a single insightful answer, a code block, or a decision explanation must manually select text from their terminal, which is error-prone and loses formatting.

Proposed Solution

Add a new slash command that copies the current assistant message to the system clipboard:

/copy

This should behave similarly to Claude Code's message copy action — copying only the most recent AI response, not the entire conversation history.

Expected Behavior

• /copy: Copies the current assistant response (the latest AI message in the active turn) to the system clipboard in Markdown format.
• Code blocks, reasoning steps, and formatting should be preserved.
• It should not include previous user messages or earlier turns.
• Full conversation history export is a separate concern and can be addressed by a potential future /export command.

Use Cases

1. Save a code snippet: Quickly copy a generated function or fix to paste into an editor.
2. Document a decision: Copy the agent's reasoning for a specific choice.
3. Share an explanation: Forward a concise answer to a colleague without including the full back-and-forth.
4. Prompt iteration: Reuse a well-written response as a template.

Alternatives Considered

• Manually selecting text in the terminal: breaks formatting and is hard for long responses.
• Terminal buffer copy-paste: includes surrounding UI noise (timestamps, prompts, etc.).

Additional Context

This is a small but high-impact quality-of-life feature that makes the terminal agent feel more polished for daily workflows. Thank you for considering this request!

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中文版

问题

目前 Kimi Code CLI 没有内置方式一键复制当前 AI 回复。用户若想保存某一条有价值的回答、代码片段或决策说明，只能在终端里手动选中文本复制，既容易出错又会丢失格式。

建议方案

新增一个 slash 命令，将当前助手消息复制到系统剪贴板：

/copy

行为上建议参考 Claude Code 的复制当前消息功能：仅复制最新一条 AI 回复，不包含完整对话历史。

预期行为

• /copy：将当前助手回复（活跃轮次中的最新 AI 消息）以 Markdown 格式复制到剪贴板。
• 保留代码块、推理过程和原始格式。
• 不包含之前的用户消息或更早轮次的内容。
• 完整对话历史导出是另一个独立需求，可通过未来的 /export 命令实现。

使用场景

1. 保存代码片段：快速复制生成的函数或修复方案，粘贴到编辑器中。
2. 记录决策依据：复制 Agent 对某个选择的推理过程。
3. 分享 concise 答案：把一条清晰的解释转发给同事，无需带上完整来回对话。
4. Prompt 复用：将写得好的回答作为模板复用。

已考虑的替代方案

• 手动在终端里选中复制：容易破坏格式，且长回复很难操作。
• 终端缓冲区复制：会带上周围的 UI 干扰（时间戳、提示符等）。

补充说明

这是一个小而高频的易用性改进，能让终端 Agent 在日常工作流中更顺手。感谢团队考虑这个需求！

No files or tests are named. Start by tracing the existing slash-command handling and how the active assistant response is stored, then identify the project's clipboard integration point. Done means /copy preserves the latest response's Markdown and formatting without including earlier turns; verify this through the CLI with code blocks and multiple messages.