Add keybinding to clear input box without cancelling in-progress tool calls

Feature request

Currently, pressing Escape (or Ctrl+C) clears the input box but also cancels any in-progress tool call. There is no way to clear only the typed text without interrupting an ongoing operation.

Expected behaviour

A dedicated keybinding (e.g. Escape, or a configurable binding) that clears the current input text only — without cancelling tool calls that are running in the background.

Current behaviour

Escape and Ctrl+C both act the same way: they cancel the in-progress tool use AND clear the input. If the user accidentally types something and wants to clear the input while Claude is working, they have no safe way to do so.

Why it matters

Users working on longer tasks (multi-step tool calls, repo analysis, etc.) sometimes want to clear a mistakenly typed message while Claude is still working. Today the only option interrupts the work entirely.