> the goal of dismissing the app to "Tray" is to lessen the perf hit of startup cycles

Thi is something that is normally done by asking the user first.

> I do send an OS notification right away

This isn’t effective because when your application is run for the first time, it doesn’t have permission to send notifications. So when the user tries to quit for the first time, they won’t be told it’s still running, they’ll get asked to receive notifications. You should use something other than notifications for this.