Cross-app session sync between Copilot CLI and Copilot Desktop App

### Describe the feature or problem you'd like to solve

I use both the GitHub Copilot CLI and the Copilot desktop app on macOS. Currently, sessions started in the CLI are not visible or accessible in the desktop app, and vice versa. It would be very useful to have sessions synced (or at least importable/resumable) across both interfaces, so I can seamlessly switch between a terminal and desktop workflow without losing context. Suggested improvements: • Show CLI sessions in the desktop app's session list • Allow resuming a CLI session from the desktop app (and vice versa) • Or at minimum, a one-click export/import between the two

### Proposed solution

_No response_

### Example prompts or workflows

_No response_

### Additional context

_No response_

從 Copilot CLI 的工作階段與繼續工作入口，以及 macOS 桌面應用程式的工作階段清單開始。比較每個介面如何呈現工作階段，然後判斷同步還是一鍵匯入/匯出更適合此工作流程。當工作階段可以在兩個介面中被找到並繼續，或在兩者之間傳輸時，即視為完成。

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