Question tool: allow attaching screenshots/images to answers (paste or + button)

Feature hasn't been suggested before.

• I have verified this feature I'm about to request hasn't been suggested before.

Describe the enhancement you want to request

The problem

The question tool's answer path is text-only: the user can pick options or type a string. When the question is inherently visual — "which of these two UI states?", "does this layout match what you see?", "which mock is right?" — the model must describe the visual in words, ask the question, and the user must answer in words, with no way to point at pixels. Meanwhile chat itself accepts image attachments fine, so the capability exists in the product but not at the moment of choice.

Concretely, when I ask "does this render correctly?" I can't attach "here, look" — I have to cancel the question, paste the screenshot into the composer, and re-ask. The question card becomes a dead end for the most common visual-debugging loop.

What I'd like to add

Two complementary affordances, either alone would already help:

1. Paste into free-text — with the free-text/"Other…" field focused, paste an image from the clipboard. It attaches to the answer like a chat attachment.
2. A "+" attachment button next to the free-text field — opens a file picker (or screenshot capture) and attaches the image to the answer.

Acceptance

• An image can be attached to a question answer (via paste or picker)
• The answer envelope carries the attachment(s) through question.replied so client implementations can forward them into the session
• Questions without attachments behave exactly as today (purely additive)

Out of scope

• Rendering/annotating images inside the question card
• Non-image attachments