[Feature Request] Make cancel key configurable or require confirmation for Escape

Question

**Bug Description**
  As a vim user, I frequently press Escape out of habit to deselect or exit modes.
  In Claude Code, this cancels the current operation, which is disruptive.

Request: Add one of these options:
  1. Require double-Escape to cancel (single Escape does nothing)
  2. Make the cancel key configurable in settings
  3. Add a brief confirmation before canceling long-running operations

This affects many developers who use vim keybindings daily.

**Environment Info**
- Platform: