fix issue

apps/edr-freight-api/src/modules/train-scheduling/utils/fleet-plan.util.ts

@@ -35,11 +35,34 @@ export type DeferredBookingRow = {
   shortage?: BookingWagonShortage | null;
 };
 
+/** A booking the customer has already paid for. */
+const isPaid = (booking: Booking): boolean =>
+  booking.paymentStatus === 'PAID' || booking.status === 'PAID';
+
+/**
+ * Seating order for the wagon planner.
+ *
+ * Government first, then PAID bookings, then priority score, then date.
+ *
+ * Payment ranks above priority score on purpose: money has changed hands and
+ * the customer was promised space on THIS train. Without it the planner
+ * seated an unpaid booking that merely arrived earlier and left a paid one
+ * with no wagon — the reported S-2026-00045 case, where a paid 695T bulk
+ * booking lost every wagon to unpaid container bookings and vanished from
+ * the train with free PW2 still standing in the consist.
+ *
+ * This only decides who is seated FIRST when the train is oversubscribed. It
+ * never invents capacity: an oversubscribed train still defers someone, and
+ * that someone is now the party who has not paid.
+ */
 export function sortBookingsForScheduling(bookings: Booking[]): Booking[] {
   return [...bookings].sort((a, b) => {
     const govDiff = Number(Boolean(b.isGovernment)) - Number(Boolean(a.isGovernment));
     if (govDiff !== 0) return govDiff;
 
+    const paidDiff = Number(isPaid(b)) - Number(isPaid(a));
+    if (paidDiff !== 0) return paidDiff;
+
     const priorityDiff = (b.priorityScore ?? 0) - (a.priorityScore ?? 0);
     if (priorityDiff !== 0) return priorityDiff;