No keyboard shortcut to interrupt a running turn

[ChristmasSun]

What

There is no keyboard way to stop a running turn, and nothing bindable for it in Settings → Keybindings.

Today the only path is clicking the square stop button. The composer registers ArrowDown, ArrowUp, Enter and Tab as command keys, and the keybinding command list has no interrupt entry, so there is nothing to rebind either.

Why it matters

Codex and Claude Code both stop the agent on Escape, so the muscle memory already exists — you notice a turn going the wrong way, hit Escape, and clarify. In T3 Code that same reflex does nothing and you have to move to the mouse.

Proposed shape

Register thread.interrupt as a keybinding command defaulting to Escape, so it shows up in Settings as a normal rebindable row rather than a hard-coded key.

Two details that seem worth agreeing on before the code matters:

• The shortcut should only be claimed while a turn is actually running, so Escape keeps its existing behavior everywhere else.
• The default should be scoped to !terminalFocus so Escape still reaches the terminal.

Happy to close this if it is not a direction you want. Opening per CONTRIBUTING since it adds a command to packages/contracts.

Prior art in this repo

#4298 did this as a hard-coded Escape in the composer and was closed. Making it a keybinding instead means it can be rebound, which seems like the better shape.