This PR introduces a component for the terminal tool call's header. It
was growing already pretty big in the terminal tool call render function
in the thread view and hard to visualize in all of its use cases. I got
motivated to do this because I wanted to make the UI for the case when
it runs outside of the sandbox simpler, but it wasn't easy to make that
show up in a true agent thread, and with it being a component, I can
just use the component preview.

Here's a quick screenshot of it, it shouldn't look too different, just a
bit more polished:

<img width="600" alt="Screenshot 2026-07-13 at 6  43@2x"
src="https://github.com/user-attachments/assets/fb222e50-2003-4cf7-9039-7b211db3c86e"
/>

Release Notes:

- N/A