feat(freight): basics of train scheduling

apps/edr-freight-api/src/modules/train-sets/entities/train-set-wagon.entity.ts

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+import { BaseEntity } from '@edr/api-common';
+import { Column, Entity, Index, JoinColumn, ManyToOne, OneToMany } from 'typeorm';
+
+import { WagonBookingAllocation } from '../../train-schedules/entities/wagon-booking-allocation.entity';
+import { WagonType } from '../../wagon-types/entities/wagon-type.entity';
+import { TrainSet } from './train-set.entity';
+
+@Entity({ schema: 'freight', name: 'train_set_wagons' })
+@Index(['trainSetId', 'sequenceNo'], { unique: true })
+export class TrainSetWagon extends BaseEntity {
+  @Column({ name: 'train_set_id', type: 'uuid' })
+  trainSetId!: string;
+
+  @ManyToOne(() => TrainSet, (trainSet) => trainSet.wagons, { onDelete: 'CASCADE' })
+  @JoinColumn({ name: 'train_set_id' })
+  trainSet?: TrainSet;
+
+  @Column({ name: 'wagon_type_id', type: 'uuid' })
+  wagonTypeId!: string;
+
+  @ManyToOne(() => WagonType, (wagonType) => wagonType.trainSetWagons)
+  @JoinColumn({ name: 'wagon_type_id' })
+  wagonType?: WagonType;
+
+  @Column({ name: 'sequence_no', type: 'int' })
+  sequenceNo!: number;
+
+  @Column({ name: 'capacity_tons', type: 'numeric', precision: 10, scale: 3 })
+  capacityTons!: number;
+
+  @Column({ name: 'length_meters', type: 'numeric', precision: 10, scale: 3 })
+  lengthMeters!: number;
+
+  @Column({ name: 'assigned_weight_tons', type: 'numeric', precision: 10, scale: 3, default: 0 })
+  assignedWeightTons!: number;
+
+  @OneToMany(() => WagonBookingAllocation, (allocation) => allocation.trainSetWagon)
+  allocations?: WagonBookingAllocation[];
+}