David decided: simulation must use production machinery

Kerra has a simulation mode used to test onboarding, course sync, change detection, calendar work, and monitor agents without waiting for real academic time to pass.

David's objection was to building a separate fake change-detection loop for simulation. The simulation should use the same production machinery, with only the time window changed to simulated time.

there shoudlnt be a parallel simulation-mode change detection system. gut it and delete it. it should use the same one that the production uses.

The mental model is conservative: if simulation does not exercise the same production path, it proves the wrong thing.