[IMPROVEMENT] Commit messages should be cached temporarily when rejected

So, this is mainly just a token and time efficiency thing, sometimes claude gets overzealous and tries to commit and push before it gets everything write, but it completes a commit message that is 95% correct and maybe needs 1-2 lines changed.

But when you hit no, the message is lost and then even if it changes a single line, it generates an entirely new commit message and is often less accurate (especially if it decides it needs to compact right after).

A similar improvement was made to plan mode where rejected plans still appear in the window so I don't think this should be too hard to implement and its just a waste of tokens when it can just append a line and reuse the original message.