Pending migrations show one reminder at login
A change merged into quattro marks the pending-migrations reminder transient, so the card is shown and never written to live.json. A machine whose migrations stay pending had gained one identical card per login.
While migrations are pending, a critical reminder goes out at every login, and the shell restores the last card beside the new one.
emirb saw 15 cards after 15 logins on a virtual machine, pushing the first-run cards off the screen. One click on the card clears it. With the change, three logins in a row each showed one reminder, and live.json held only the three first-run cards.
If the shell restarts during a session, the reminder is gone until the next login. Reminder cards that rc1 or rc2 already stored stay until they are dismissed.