<img width="707" height="778" alt="Screenshot 2026-01-07 at 8 34 00 PM"
src="https://github.com/user-attachments/assets/59842820-079b-4d47-9bdd-f77300f8a60e"
/>

When the user presses Esc or the Stop button to interrupt a thread,
terminal tools now capture their output and include it in the tool
result. This allows the model to see what was happening in the terminal
when the user interrupted, so it can answer questions about the output.

## Changes

- `Thread::cancel()` now returns a `Task` that waits for tools to
respond to cancellation before flushing pending messages
- Terminal tool uses `select!` to detect cancellation signal and
immediately kills the terminal and captures output
- `run_turn_internal` uses `select!` to break out of event loop on
cancel
- Added test for terminal tool cancellation output capture

This is a follow-up to #46218 which added similar functionality for the
"Stop" button on individual terminal tool cards.

Release Notes:

- Interrupting the agent now captures terminal output so the model can
see what was running when you stopped it