LLM kept mentioning agent mode, still don't know what it means even.

LLM kept mentioning agent mode, still don't know what it means even. It description just made it sound like a code session instead of chat session. but that agent doesn't appear on the ui as far as i can tell.

In Copilot Chat (**Agent** mode), open tools and start the `godot` server.

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| Field | Value |
| --- | --- |
| App version | 1.0.23 |
| OS | Windows 10.0.19045 |
| Theme | Monochrome |
| Path | /chat |
| Tenure | Week 3 |

使用 Copilot Chat Agent mode，在 /chat 路径中复现该报告，打开工具并启动 godot 服务器。检查 UI 中是否出现 Agent mode，以及其描述是否区分 agent 会话和 chat 会话。完成标准是该模式可被发现，并且其说明与观察到的行为一致。

由索引模型根据 Issue 内容生成。