Allow paste images into freeform question input

Describe the feature or problem you'd like to solve

When the CLI agent asks a question via its interactive "Question" prompt UI, and you use the freeform text answer (either a no-choices question, or selecting "Other (type your answer)" on a multiple-choice question), the resulting input box does not accept pasting of screenshots

Proposed solution

If Copilot is going to use the freeform answer to ask me a question, i need the ability to paste a screen shot just like i would if i was answering Copilot normally

Example prompts or workflows

No response

Additional context

No response

首先跟踪 CLI agent 的交互式 Question prompt UI 及其自由文本输入处理。将其与正常回答 Copilot 时使用的现有输入路径进行比较，然后验证无选项问题和“Other (type your answer)”流程两种情况下的行为。完成的标准是两种自由文本情况下都可以粘贴截图。