add wagon allocation snapshot to train schedules

packages/types/src/freight/index.ts

@@ -237,6 +237,42 @@ export enum WagonReadiness {
   ExportReady = "EXPORT_READY",
 }
 
+/**
+ * Frozen record of one wagon slot's allocation at the moment a schedule leaves
+ * DRAFT/SCHEDULED (dispatch / arrive / cancel). Captured once into
+ * `train_schedules.wagon_allocation_snapshot` so the historical wagon plan
+ * survives later re-pinning of the same physical wagons onto other trains.
+ */
+export interface WagonAllocationSnapshotSlot {
+  sequenceNo: number;
+  trainSetWagonId: string;
+  physicalWagonId: string | null;
+  physicalWagonNumber: string | null;
+  wagonTypeId: string | null;
+  wagonTypeCode: string | null;
+  /** Wagon slot status (RESERVED/LOADED/…) at capture time. */
+  slotStatus: string | null;
+  boardYardId: string | null;
+  alightYardId: string | null;
+  allocations: WagonAllocationSnapshotAllocation[];
+}
+
+export interface WagonAllocationSnapshotAllocation {
+  bookingId: string;
+  bookingReference: string | null;
+  allocatedWeightTons: number;
+  loadType: string | null;
+  containerNumbers: string[];
+}
+
+/** Whole-schedule frozen wagon plan written at a terminal/transit transition. */
+export interface WagonAllocationSnapshot {
+  /** Schedule status the snapshot was captured at (DISPATCHED/ARRIVED/CANCELLED). */
+  capturedStatus: string;
+  capturedAt: string;
+  slots: WagonAllocationSnapshotSlot[];
+}
+
 export type ScheduleTradeDirection = "IMPORT" | "EXPORT" | "DOMESTIC";
 
 /**