Everyone's photos. One question: whose is whose?

Stateless bulk sweeps, not a timer per game

The obvious build schedules a timer when each game is created. It also falls apart the moment you run more than one server: clocks drift, restarts drop jobs, and you are left babysitting thousands of dangling timers.

So we made the state changes stateless and idempotent. Every scheduler tick runs a few updateMany queries keyed on dates: any number of games that are due move forward in a single query. The job is safe to run twice, and a missed run simply heals itself on the next tick. There is no per-game state to lose.