The countdown sent from inside a state updater and Undo's button submitted the
form, so Undo stopped the timer and then started the send over. The timer is
now held in a ref, Undo is type=button, and leaving the screen flushes a
pending send once. Snippets drop a stylesheet the preview was cut inside of.
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
