feat(train): enhance train history and scheduling features

- Added a reason field to train history entries for detach/maintenance actions.
- Updated TrainHistoryPanel to display the reason for wagon detachments.
- Introduced per-wagon load/unload functionality in ScheduleWorkspacePanel with a modal for managing individual wagons.
- Implemented API endpoints for loading and unloading specific wagons, including the ability to cancel remaining wagons with a reason.
- Refactored detach request handling in TrainBuilderDetailPage to streamline the process and remove the approval flow, requiring a reason for detachments.
- Updated types and services to support new wagon loading/unloading features and booking wagon retrieval.

apps/edr-freight-api/src/modules/bookings/dto/wagon-cancellation.dto.ts

@@ -3,9 +3,11 @@ import { Type } from 'class-transformer';
 import {
   ArrayNotEmpty,
   IsArray,
+  IsBoolean,
   IsDateString,
   IsIn,
   IsInt,
+  IsNotEmpty,
   IsNumber,
   IsOptional,
   IsString,
@@ -169,3 +171,28 @@ export class FilterWagonCancellationsDto {
   @Min(1)
   pageSize?: number;
 }
+
+/**
+ * Staff cancel of the never-loaded remainder of a booking mid-load: everything
+ * not yet LOADED on the schedule is cut, the booking shrinks to its loaded
+ * wagons, and the freed credit is rebookable. Fault decides the fee: CUSTOMER
+ * — cancellation fee invoiced (payable after the cut); EDR — no fee.
+ */
+export class CancelRemainingWagonsDto {
+  @ApiProperty({ description: 'Schedule the booking is being loaded on' })
+  @IsUUID('4')
+  scheduleId!: string;
+
+  @ApiProperty({ description: 'Why the remaining wagons are not riding' })
+  @IsString()
+  @IsNotEmpty()
+  @MaxLength(2000)
+  reason!: string;
+
+  @ApiPropertyOptional({
+    description: 'The shortfall is EDR\'s fault (wagon shortage, yard problem) — no fee charged',
+  })
+  @IsOptional()
+  @IsBoolean()
+  edrFault?: boolean;
+}