[BUG] Improve stash reliability

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Stash isn't saved to disk or any sort of history, so if a stashed prompt is lost it's gone forever. This makes the feature somewhat useful for small prompts, but not reliably enough to actually be part of a workflow. It calls for a separate notepad somewhere to write prompts.

What Should Happen?

Stashed prompts should be saved not only to disk, but to a stash stack so they can be pushed, popped, or dropped, like the git stash.

Error Messages/Logs

Steps to Reproduce

1. Type something, press ctrl + s to stash
2. Type something else, press ctrl + s again
3. Previous stash is lost (overwritten)

or

1. Type something, press ctrl + s to stash
2. See a Claude Code error 500 or another bug cause the stash to be lost
3. No way to recover it

Claude Model

Opus

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

2.1.45

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

iTerm2

Additional Information

_No response_