refactor(train-scheduling): rename and restructure container movement logic

apps/edr-freight-api/src/modules/train-scheduling/dto/move-container-item.dto.ts

@@ -1,14 +0,0 @@
-import { IsOptional, IsUUID } from 'class-validator';
-
-export class MoveContainerItemDto {
-  @IsUUID()
-  targetTrainSetWagonId!: string;
-
-  /**
-   * Swap with this container on the target wagon instead of requiring free
-   * space there. Same-wagon swaps exchange the two slot positions.
-   */
-  @IsUUID()
-  @IsOptional()
-  swapWithItemId?: string;
-}

apps/edr-freight-api/src/modules/train-scheduling/dto/move-wagon-load.dto.ts

@@ -0,0 +1,11 @@
+import { IsUUID } from 'class-validator';
+
+export class MoveWagonLoadDto {
+  /**
+   * Where the source wagon's whole load goes: a train-set wagon slot (empty →
+   * move, loaded → swap the two loads) or an empty consist-only physical wagon
+   * of the built train (→ the slot repins onto it).
+   */
+  @IsUUID()
+  targetWagonId!: string;
+}