Use `tmux` instead of `screen` in agentic modules

[stirby]

Currently, our claude-code and goose modules use screen (in a hacky way) to persist chat history and terminal sessions.

We should add support for persistence using the newer and cleaner tmux package. Deprecating the screen implementation is not a part of this work but is worth consideration in a follow-up.

tmux may also allow us to persist the session across workspace restarts using tmux-resurrect and tmux-continuum.

[DevelopmentCats]

Claude-Code, and the Aider module both use t-mux.

I will go ahead and add t-mux support to goose as well.