Zen-mode keyboard shortcut

Would it be possible to add keyboard shortcut (such as e.g. Ctrl-z) to toggle zen-mode? And if so, also disable how ESC-key takes you out from zen-mode (since it interferes with going into command mode)?

No files, tests, or entry points are named. Start by locating the zen-mode behavior and keyboard-shortcut handling, then verify that a shortcut toggles zen mode and that Escape no longer exits it while command mode remains usable.

Written by the indexing model from the issue text.