ok  schema has tray_rate, discount_percent, manual_discount_cents, colours
ok  admin UI copy, print discount, colour filter, and gantt controls are wired
ok  per-user Override Discount Rate changes wholesale pricing
ok  colour metafield parsing and CSV import work
ok  default 1-day boxes stagger to the staff tray rate and overflow to the next day
ok  conflicts list every tray that exceeds a staff member's daily rate
ok  Manual Discount subtracts from the billable total as Additional Discount
schedule tray-rate / discount / colour checks passed