Addition of `/editor` command?

[thehunmonkgroup]

Issue

Over at https://github.com/llm-workflow-engine/llm-workflow-engine I've implemented a very handy /editor command that:

• Opens the CLI editor as specified in the $EDITOR environment variable, right within the context of the running program
• Upon close/save of the editor, pipes the final editor contents back to the program as input

As a Vim/Neovim user, this is super handy for working on more complex prompts, as I have my full editor seamlessly integrated into my workflow.

While LWE and Aider serve completely different purposes, I noticed Aider also uses Prompt Toolkit, and I bet it would be fairly easy to lift the existing /editor command code from LWE and port it to Aider.

If you think this is a worthwhile feature addition, I might be willing to work on the PR to accomplish this, but I wanted to check for interest before I did any heavy lifting.

Version and model info

N/A