Copilot cli dialog enhancement

Describe the feature or problem you'd like to solve

Confusion and dificulty entering prompts and resonses leading to errors

Proposed solution

Adding a built-in floating GUI prompt composer: large accessible text, word wrap, dark theme, Enter to return the draft, and no clipboard dependency. This greatly improves accessibility, spelling, and long-prompt composition. My copilot made one for me and it is a game changer, especially if you are visually impaired.

Example prompts or workflows

No response

Additional context

No response

未指定文件、测试或入口点。首先定位 CLI 的提示输入流程，并查看交互式终端输入的处理方式；完成的标准是：内置的无障碍浮动 composer 支持大号自动换行文本、深色主题，按 Enter 返回草稿，并且不依赖剪贴板。