feat(train-scheduling): auto-place intercity cargo on wagons freed mid-corridor

Intercity bookings ride the wagons freed by earlier unloads (e.g. import
containers uncoupled at Dire Dawa). loadBooking now auto-allocates a
DOMESTIC booking onto on-train slots whose cargo has all departed —
greedy in consist order by capacity, container numbers copied for the
marshalling tally. Falls back to unallocated load when nothing is free.

apps/edr-freight-web/backoffice/src/services/trainScheduling.service.ts

@@ -624,6 +624,16 @@ export const trainSchedulingService = {
     return response.data;
   },
 
+  downloadIntercityMarshallingDocument: async (
+    scheduleId: string,
+  ): Promise<Blob> => {
+    const response = await client.get(
+      URL_CONSTANTS.TRAIN_SCHEDULING.INTERCITY_MARSHALLING_DOCUMENT(scheduleId),
+      { responseType: "blob" },
+    );
+    return response.data;
+  },
+
   getTrack: async (scheduleId: string): Promise<TrainTrackResponse> => {
     const response = await client.get<TrainTrackResponse>(
       URL_CONSTANTS.TRAIN_SCHEDULING.CHECKPOINTS(scheduleId),