“Millions of letters from state agencies — including notices of health and SNAP benefit renewal, driver’s license and vehicle registration renewal invitations, vehicle registration cards, and more — were never sent by a mail presort vendor, who was contracted by the state to tray and sort agency mail in order to save money on postage. The failure went undetected by the state for a month, until early December, when Gov. Josh Shapiro’s administration fired Harrisburg-based Capitol Presort Services and hired another vendor for a $1 million emergency contract to work through the backlog.”