Save Chats per project. ability to load after closing nvim

[iMostfa]

Hi,

1. thanks a lot for the great plugin.
2. i wanted to know if it's possible to support persisting chat on disk, currently it's only in memory, then lost when nvim is closed.

thanks a lot for you

[iMostfa]

#652

sorry, didn't see the discussions until mine was created, this's what i needed.