feat(train-scheduling): add day-level booking pool and available days query

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

@@ -109,6 +109,21 @@ export const trainSchedulingService = {
     return unwrap(response.data);
   },
 
+  /**
+   * Day-level pool: the days that have an OPEN departure on the route. Staff pick
+   * a day; the batch engine assigns the train. No capacity is returned.
+   */
+  getAvailableDays: async (
+    originYardId?: string,
+    destinationYardId?: string,
+  ): Promise<string[]> => {
+    const response = await client.get<{ days: string[] }>(
+      URL_CONSTANTS.TRAIN_SCHEDULING.AVAILABLE_DAYS,
+      { params: { originYardId, destinationYardId } },
+    );
+    return unwrap(response.data).days;
+  },
+
   runBatch: async (scheduleId: string): Promise<BatchBoardScheduleDetail> => {
     const response = await client.post<BatchBoardScheduleDetail>(
       URL_CONSTANTS.TRAIN_SCHEDULING.RUN_BATCH(scheduleId),