fix(display): a WiFi notice preempts the current screen and Vegas yields to it (#712)

A WiFi notice preempts the current screen within about a second (frame loops, post-loop check, make-up dwell), and an interrupted Vegas iteration that yielded for a notice ends the pass so the notice shows next. Goldens: wifi_notice, vegas. First of three run-loop fixes (#712, #713, #714), pre-tested together.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

CHANGELOG.md

@@ -93,6 +93,14 @@ policies are unchanged.
   the plugin leaves rotation until the cooldown ends, the same as a raising
   `update()`. The display still moves straight on to the next mode. A hung
   `display()` is still recorded once, as a hang.
+- A WiFi notice (such as "Connected to HomeNet" or "AP mode on") now shows
+  within about a second of being posted. It was only checked between
+  screens, so a 5 s notice posted during a 20 s screen expired before that
+  screen ended and never appeared. The screen it interrupts comes back in
+  full once the notice ends. When Vegas stops scrolling for a notice, the
+  notice is what shows next, and Vegas resumes after it; before, a rotation
+  screen showed instead and the notice expired behind it. An active
+  on-demand session still holds the panel until it ends.
 
 ## 3.8.0