feat: add per-ton cargo loading limits and update related services

apps/edr-freight-api/src/modules/rule-engine/entities/cargo-type.entity.ts

@@ -60,6 +60,17 @@ export class CargoType extends BaseEntity {
   @Column({ name: 'items_per_wagon_map', type: 'jsonb', nullable: true })
   itemsPerWagonMap?: Record<string, number> | null;
 
+  /**
+   * PER_TON (bulk) only: the most tons of THIS cargo that may ride one wagon of
+   * each allowed type, keyed by wagon-type id (e.g. sugar → { NW5: 50 } on a
+   * 70T wagon). Caps both the wagon count and how much each wagon is loaded, so
+   * 200T of sugar takes 4 wagons at 50T rather than 3 at 70T. A missing key (or
+   * a null map) means the wagon's full rated capacity — unlike itemsPerWagonMap
+   * this is optional, so cargo without a loading limit is unaffected.
+   */
+  @Column({ name: 'tons_per_wagon_map', type: 'jsonb', nullable: true })
+  tonsPerWagonMap?: Record<string, number> | null;
+
   @Column({ name: 'requires_director_approval', type: 'boolean', default: false })
   requiresDirectorApproval!: boolean;