[Requests and ideas] Add a Tab sytem like a browser.

**Mood:** 😊
**Category:** Requests and ideas

Add a Tab sytem like a browser. I want to have one instance of Github Copilot open, but I want to be able to switch between sessions by going between Tabs. If I close it with three tabs open, then open it next time with those same three tabs. Let me decide when to close a tab.

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| Field | Value |
| --- | --- |
| App version | 1.0.6 |
| OS | Windows 10.0.26200 |
| Theme | GitHub |
| Path | /chat |
| Tenure | Week 6 |

从应用的 /chat 体验入手，梳理多个会话应如何以标签页的形式显示。定义切换会话、显式关闭标签页以及在应用重启后恢复已打开标签页时的预期行为。完成的标准是在 Windows 上一致地实现这三个工作流。

由索引模型根据 Issue 内容生成。