[FEATURE] Make the 'x' icon larger in the VS Code conversation pane!

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

<img width="485" height="567" alt="Image" src="https://github.com/user-attachments/assets/5c933486-6775-4520-ba6c-f45834d4e5df" />

There is an X icon overlaid on screenshots in the VS Code chat window. However, it is almost impossible to see in certain themes, given that it is white and only appears when hovering over the screenshot. Until recently, I did not even see that it existed.

<img width="510" height="574" alt="Image" src="https://github.com/user-attachments/assets/3f8a02ef-e450-401e-9d8d-635200969687" />

Proposed Solution

For unambiguous UI, white X on a black background that is always present, so it's obvious and easy to see where to remove images from a turn.

Alternative Solutions

_No response_

Priority

Medium - Would be very helpful

Feature Category

CLI commands and flags

Use Case Example

_No response_

Additional Context

_No response_