Terminal output is clipped after resize/reflow and hidden text is not reachable via scrollbar

### Describe the bug

### Description

In recent versions of GitHub Copilot CLI, long responses are sometimes not fully visible in the terminal. The missing text is not reachable using the terminal scrollbar.

The issue appears to be related to terminal resizing / reflow. When I resize the terminal window, the same response is rendered differently: sometimes more text is visible, sometimes less. In some layouts, parts of the final response are clipped even though they become visible after resizing to a different width.

### Expected behavior

All generated output should remain accessible after rendering.

If the response is longer than the visible terminal area, I should be able to reach the hidden text through normal terminal scrolling. Resizing the terminal should reflow the output without losing or hiding any content.

### Actual behavior

Parts of the generated response become hidden or clipped.

The hidden text cannot be reached with the terminal scrollbar. Resizing the terminal changes which parts of the response are visible, but does not reliably make the full output accessible.

### Example

Copilot CLI produced a response containing multiple sections/options. Earlier in the output, I could see that the response included “Option C”. However, in the final rendered summary, the text was cut off and only part of the options were visible.

After resizing the terminal:
- in one width, the final summary was cut off after the first option
- in another width, it was cut off differently
- in a narrower width, almost the full summary became visible

This makes it look like the content is present internally but is being clipped or incorrectly reflowed by the terminal UI.

### Notes

This seems related to terminal rendering, wrapping, or scrollback handling. The main problem is not just that the response is long, but that some text becomes unreachable after rendering.

### Affected version

GitHub Copilot CLI 1.0.53-1

### Steps to reproduce the behavior

1. Open Copilot CLI in an interactive terminal.
2. Ask for a response that produces a longer structured answer or final task summary.
3. Wait until the response is complete.
4. Resize the terminal window wider or narrower.
5. Observe that the visible text changes depending on the terminal width.
6. Try to use the terminal scrollbar to access the missing text.

### Expected behavior

All generated output should remain accessible after rendering.

If the response is longer than the visible terminal area, I should be able to reach the hidden text through normal terminal scrolling. Resizing the terminal should reflow the output without losing or hiding any content.

### Additional context

_No response_

使用 Copilot CLI 1.0.53-1 從 issue 中的重現步驟開始，接著追蹤終端機渲染、換行、調整大小/reflow 以及 scrollback 的行為。當一段較長的結構化回應能夠透過捲動始終完整存取，並且在不同的終端機寬度下進行 reflow 時不會被裁切，即表示完成。

由索引模型根據 Issue 內容生成。