Give a way to add current desk in the zsh prompt

Hi !
Desk is great, but it would be even better if it's possible to show the current desk into the zsh (for instance) prompt, in order to know where we are.

I see in the demo gif in the readme that you have a "(venv)" prepending your prompt, is there anyway to have the something but with the name of the current desk ?

Start with the README's demo and the zsh prompt integration requested in the issue. Determine how the current desk can be exposed to that prompt, then verify that the desk name appears reliably when switching desks and document the usage.

Written by the indexing model from the issue text.