support for `llm chat`

[lkonga]

Nice addon for llm, tried it and works nicely, but it doesn't support the chat subcommand, do you see any chance to make it support this?

[gianlucatruda]

Thanks for trying it and for the feedback, @lkonga.

This is also something I ultimately want, but getting it working for chat mode is going to be much harder (and potentially infeasible). That was why I originally added rich support directly into llm. See simonw/llm#571 where I had it working on both regular and chat modes. You could just build from that PR's fork and it'll work, but it's not ideal.

If you know of any approach that might work for interactive chats, I'm very open to it. I'll also update this issue if I think of anything.