[Feature Request] Enhanced Emacs-style undo/kill-ring integration with C-_ and M-y support

Question

**Bug Description**
There are many ways to totally lose your typein to the claude buffer. C-Y doesn't help if user fumbles two mistakes.
For starters, C-W should not clobber the kill buffer.

Emacs has M-Y to rotate kill buffers.
Claude used to have C-_ for undo but I have not seen that work in a long time.

We don't always remember to type C-G to use emacs when we start.
Can you support a more thorough Emacs integration?
Or at least a few rotating kill buffers.

**Environment Info**
- Platform: