[FEATURE] No single shortcut to clear the entire prompt buffer without interrupting a running agent

Problem

While an agent or tool call is running, there is no single shortcut that clears the entire prompt input buffer without a side effect:

• Ctrl+C — interrupts the running agent; only clears the buffer when idle.
• Esc / Esc Esc — a single Esc interrupts the running turn; the idle double-Esc clears the draft but isn't usable mid-run.
• Ctrl+L (chat:clearInput) — redraws the screen and preserves input (it doesn't clear it).

The closest workaround is Ctrl+U (Cmd+Backspace on macOS), which deletes from the cursor to line start and, when repeated, clears across the lines of a multi-line draft. It does work mid-run without interrupting the agent — but it's one press per line, so it's impractical for a long multi-line prompt.

Request

A dedicated, rebindable action that clears the entire prompt buffer in a single keystroke without cancelling in-progress agent / tool calls. (Previously requested in #52377, closed without shipping.)

Minor: stale action name

Separately, chat:clearInput no longer matches its behavior — since v2.1.126 it redraws the screen and preserves input rather than clearing it. The name is a legacy leftover and is confusing when reading keybindings.json; renaming it would also free chat:clearInput for a real clear-input action.

Environment

Claude Code 2.1.178 (latest), macOS.