implement update train details feature: add DTO, service method, and UI modal for editing train name and run numbers

apps/edr-freight-api/src/modules/contracts/contract-clearance.service.ts

@@ -489,6 +489,11 @@ export class ContractClearanceService {
     files: Express.Multer.File[],
   ): Promise<Contract> {
     const contract = await this.contractsService.findById(contractId);
+    if (contract.status === 'AWAITING_CLEARANCE_PAYMENT') {
+      throw new ConflictException(
+        'The customs clearance service fee has not been paid yet — pay it from the portal to unlock document upload.',
+      );
+    }
     if (
       contract.status !== 'AWAITING_CLEARANCE_DOCUMENTS' &&
       contract.status !== 'CLEARANCE_UNDER_REVIEW'