feat(train-sets): implement multi-locomotive support for train sets

- Added TrainSetLocomotive entity to link multiple locomotives to a train set.
- Updated TrainSet entity to include a OneToMany relationship with TrainSetLocomotive.
- Modified the train scheduling logic to require at least two locomotives for a train set.
- Enhanced the UI components to support selecting multiple locomotives.
- Introduced new permissions for viewing customs clearance.
- Updated migrations to create the train_set_locomotives table and backfill existing data.
- Implemented utility functions for managing train numbers based on cargo type and direction.
- Added tests for train number utilities to ensure correct functionality.

apps/edr-freight-api/src/modules/train-scheduling/train-scheduling.service.spec.ts

@@ -389,8 +389,12 @@ describe('TrainSchedulingService', () => {
       isActive: true,
     };
 
+    const locomotive2 = { ...locomotive, id: 'loc-2', code: 'LOC-002' };
     const lockedLocomotiveRepo = {
-      findOne: jest.fn().mockResolvedValue(locomotive),
+      findOne: jest
+        .fn()
+        .mockResolvedValueOnce(locomotive)
+        .mockResolvedValueOnce(locomotive2),
       update: jest.fn().mockResolvedValue(undefined),
     };
     const trainScheduleRepo = {
@@ -401,6 +405,10 @@ describe('TrainSchedulingService', () => {
       create: jest.fn().mockImplementation((value) => value),
       save: jest.fn().mockResolvedValue({ id: 'train-set-1' }),
     };
+    const trainSetLocomotiveRepo = {
+      create: jest.fn().mockImplementation((value) => value),
+      save: jest.fn().mockResolvedValue(undefined),
+    };
     const manager = {
       getRepository: jest.fn((entity: { name?: string }) => {
         switch (entity?.name) {
@@ -410,13 +418,14 @@ describe('TrainSchedulingService', () => {
             return trainScheduleRepo;
           case 'TrainSet':
             return trainSetRepo;
+          case 'TrainSetLocomotive':
+            return trainSetLocomotiveRepo;
           default:
             throw new Error(`Unexpected transaction repository ${entity?.name}`);
         }
       }),
     };
 
-    jest.spyOn(service, 'selectOrValidateLocomotive').mockResolvedValue(locomotive as never);
     dataSource.getRepository.mockImplementation((entity: unknown) => {
       if ((entity as { name?: string })?.name === 'Route') {
         return { findOne: jest.fn().mockResolvedValue(route) };
@@ -437,12 +446,16 @@ describe('TrainSchedulingService', () => {
     const result = await service.createContainerTrainSchedule({
       routeId: 'route-1',
       scheduleDate: '2026-06-20T08:00:00.000Z',
-      locomotiveId: 'loc-1',
+      locomotiveIds: ['loc-1', 'loc-2'],
     });
 
     expect(trainSetRepo.save).toHaveBeenCalled();
     expect(trainScheduleRepo.save).toHaveBeenCalled();
-    expect(lockedLocomotiveRepo.update).toHaveBeenCalledWith('loc-1', { status: 'ASSIGNED' });
+    expect(trainSetLocomotiveRepo.save).toHaveBeenCalled();
+    expect(lockedLocomotiveRepo.update).toHaveBeenCalledWith(
+      { id: expect.objectContaining({ _type: 'in', _value: ['loc-1', 'loc-2'] }) },
+      { status: 'ASSIGNED' },
+    );
     expect(result.id).toBe('schedule-1');
   });
 
@@ -508,7 +521,6 @@ describe('TrainSchedulingService', () => {
       })),
     };
 
-    jest.spyOn(service, 'selectOrValidateLocomotive').mockResolvedValue(locomotive as never);
     dataSource.getRepository.mockImplementation((entity: { name?: string }) => {
       if (entity?.name === 'Route') {
         return {
@@ -531,7 +543,7 @@ describe('TrainSchedulingService', () => {
       service.createContainerTrainSchedule({
         routeId: 'route-1',
         scheduleDate: '2026-06-20T08:00:00.000Z',
-        locomotiveId: 'loc-1',
+        locomotiveIds: ['loc-1', 'loc-2'],
       }),
     ).rejects.toBeInstanceOf(ConflictException);
   });