Add Terminal Mutliplexer to support SSH sessions

[markfields]

Investigate adding a terminal multiplexer, such as tmux or screen, to the dotfiles repository. Key tasks:

1. Evaluate the pros and cons of tmux vs. screen.
2. Add a sample configuration file for the selected multiplexer.
3. Ensure key bindings and themes align with the existing dotfiles.
4. Document usage for common workflows, like detaching and reattaching sessions.