Display > Message alert: Normal keeps the sliding banner; Compact shows an
envelope with the unread count beside the battery (in the header line where
there's no status row), blinking for 2 s; Off shows nothing. The blink only
ever brings the next frame earlier, so it no longer holds back the UI's
animations while it runs.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>