[Feature] Implement branching off a chat

https://discord.com/channels/1386638085571477575/1412157962277097544/1433507845558505572

I was thinking of a nice feature for the collaborative part of the tool, I probably don't want to share my whole chat , but would be nice to start one from scratch with (for example) the MD above as starting point, clicking a button and starting a share just with that part (like ms teams does). Its not the most important feature sync copy paste is easy to do, but and idea