Leave management with atomic balances
Annual / sick / unpaid / parental / bereavement leave with pro-rated entitlements for new joiners. Balance updates run inside a Prisma transaction so balances can't desync.
in production, no sandbox here
This one runs in Broomstick Hub and Beeline Medical. It has no sandbox on this site, because the pattern only means anything against a real database, real roles, and real money. Rebuilding that as a toy would demonstrate the toy.
The write-up covers how it works and where it is deployed.