A recipient with emailStatus REQUESTED is emailed at once, without a
standing category preference or minimum severity, and only once even when
an IMMEDIATE preference also applies. No address: SKIPPED. ALERT
notifications are still never emailed here. This is the delivery half of
the durable-jobs "Email me when done" opt-in (QRun-IO/qqq durable jobs spec
2.11); marking recipients REQUESTED from core's NotificationSignal
attribute emailRequested lands with the RC.6 core notify() adoption.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>