Sound doesn't play after reboot until app is foregrounded at least once (vibrate and notification still happens)

[makoConstruct]

Theory so far: audio hardening only allows foreground processes to play sound if they were initiated by a user action or exact alarm.

This would require me to rethink the assumption that we could get away with not asking for exact alarm permission. If we do, it'll probably be a good idea to replace async.Timers with alarm handles.

[makoConstruct]

Also: notifications don't start.

This is the part where the issue actually becomes severe, since it'll be pretty common for a user to have both persistent alarms on, and to have one cross a restart boundary, and the symptom is continual repeated vibration with no apparent cause.