#433 auth dialog: show a live countdown instead of a static "auto-denies in 2m"

[Anonymous]

Originally created by: fu351

The dialog's message ends with deadline_note(DEFAULT_DIALOG_TIMEOUT_S) ("auto-denies in 2m if unanswered"), appended once when the segments are built (src/doberman/auth/gui_prompter.py:240). The auto-deny itself is a single root.after(int(timeout_s * 1000), root.quit) (:526). A human who walks back with ten seconds left still reads "2m".

What to do

1. Keep the auto-deny exactly as it is. This issue only changes what the deadline line says.
2. Render the deadline segment so it can be updated in place (tag the range in the Text widget, or draw it as its own canvas text item), then add a _tick() that recomputes the remaining seconds from the dialog's start time and rewrites that segment every second via root.after(1000, _tick). Stop ticking when the root is destroyed.
3. Format the text with the existing deadline_note helper if it accepts seconds, otherwise a plain auto-denies in 45s if unanswered. Keep it muted like today.
4. Test in tests/unit/test_gui_prompter.py with the faked root: two simulated ticks change the deadline text, and the after that arms the auto-deny is still scheduled exactly once with the same delay.

The timeout value and the deny-on-timeout behaviour stay untouched; a test pinning that already exists and must stay green.