The first step was not to fix anything. It was to measure. One ordinary shift was rebuilt as a scenario that can be replayed: 120 orders over five hours, 60 scheduled runs, and the interruptions that really happen — the shop's website restarting for seven minutes, the email service hitting its daily limit, three orders published a few minutes late, four customers correcting their address after ordering, one customer with a single name, one with no phone number, one with an empty email field, one address that bounces forever.