Feature Request / Proposal: fork session from message via CLI + copy command message dialog

[nocksock]

I would often opencode -c in a new terminal, just to use /timeline to fork the session at a certain point. This way I can use /timeline and copy a command that forks a session at the selected message.

It would be cool, if there was a way to create a user-land function/hook that could get called from that message dialog. That way one could create a "fork in new terminal window" (or tmux/zellij-pane or whatever). Which is more complex - and I'm not yet familiar enough with opencode's source and direction - and would need this functionality anyway I guess.