Allow the model to get context from other sessions #968

Description

Sometimes I find myself using multiple sessions to achieve different tasks, and in those sessions I'll ask for specific behaviors for the model.

Would be great that from a session I could trigger a command like /link and then I have a selector to link a session or multiple sessions to that chat. Once I have this, I could ask the model to create a comprehensive AGENTS.md file that has context from all sessions.

Example

I'm currently working on implementing multiple similar workflows, but they need to eventually follow the same implementation steps.
Even with some README.md files that declare the steps to follow, the model end up adding specific checks that are not needed as already done in helper functions. So I correct the model in different sessions to tackle the refactor quickly.
After all this manual verification, it would be great to create a new session, where I can link all those small sessions, and ask the model to update AGENTS.md, so it doesn't do the same issues (about not using the helper functions).

Possible other cases

You've done something in one session (A), and you want to fork that state to a new session (B) to iterate on a new idea.
Then you'll create a new session (B), and use /link session(A), and all that state will be brought to the model on session (B).

I'll be happy to do a PR for it if this feature could be useful to others and is not in the roadmap yet 🙌🏻

PS: No strong opinion on how this could look like (a command, an export function and then linking the file/folder to the chat). Let me know what do you guys think is more useful.