feat(intercity): raise a GRN when a facility loads or unloads cargo

Every facility raises a GRN — the goods changed hands, whether or not anyone
stores them. What differs is what happens next: Indode has a warehouse, so cargo
left there goes through the existing warehouse flow and accrues storage and
demurrage; Sebeta, Modjo, Adama and Dire Dawa only move cargo between train and
truck, so the handling event and its GRN are the whole record.

facility_handling_events carries that record because warehouse_inventory cannot:
its warehouse/yard/zone are NOT NULL, so a facility with equipment but no
warehouse could never have a row there. inventory_id links the storage record
when the facility does keep the cargo, which is what ties an Indode handover to
its demurrage.

generateGrnNumber moves to common/grn.util.ts so a GRN raised at a facility is
indistinguishable from one raised in a warehouse — the two live in different
tables, and a second generator would let the formats drift.

Recording is best-effort: the cargo moved regardless, so paperwork must never
fail the journey.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

apps/edr-freight-api/src/modules/train-scheduling/entities/facility-handling-event.entity.ts

@@ -0,0 +1,56 @@
+import { BaseEntity } from '@edr/api-common';
+import { Column, Entity, Index } from 'typeorm';
+
+export const FACILITY_HANDLING_EVENT_TYPES = ['LOAD', 'UNLOAD'] as const;
+export type FacilityHandlingEventType = (typeof FACILITY_HANDLING_EVENT_TYPES)[number];
+
+/**
+ * Cargo loaded onto or unloaded off a train at a yard's facility, and the GRN
+ * raised for it.
+ *
+ * This exists because warehouse_inventory can't do the job: its
+ * warehouse/yard/zone are NOT NULL, so a facility that only has equipment and no
+ * warehouse (Sebeta, Modjo, Adama, Dire Dawa) could never have a row there —
+ * yet it still hands cargo over and still needs a GRN.
+ *
+ * `inventoryId` links to the warehouse record when the facility does store cargo
+ * (Indode), which is what makes storage and demurrage accrue there and nowhere
+ * else.
+ */
+@Entity({ schema: 'freight', name: 'facility_handling_events' })
+@Index(['bookingId'])
+@Index(['yardId'])
+export class FacilityHandlingEvent extends BaseEntity {
+  @Column({ name: 'booking_id', type: 'uuid' })
+  bookingId!: string;
+
+  /** The facility yard where the cargo was handled. */
+  @Column({ name: 'yard_id', type: 'uuid' })
+  yardId!: string;
+
+  /** The train the cargo came off / went onto. */
+  @Column({ name: 'train_schedule_id', type: 'uuid', nullable: true })
+  trainScheduleId?: string | null;
+
+  @Column({ name: 'event_type', type: 'varchar', length: 10 })
+  eventType!: FacilityHandlingEventType;
+
+  @Column({ name: 'grn_number', type: 'varchar', length: 60, nullable: true })
+  grnNumber?: string | null;
+
+  @Column({ name: 'quantity', type: 'numeric', precision: 14, scale: 3, nullable: true })
+  quantity?: number | null;
+
+  @Column({ name: 'weight_tons', type: 'numeric', precision: 14, scale: 3, nullable: true })
+  weightTons?: number | null;
+
+  /** Set only when the facility stores cargo (has_warehouse) — the storage record. */
+  @Column({ name: 'inventory_id', type: 'uuid', nullable: true })
+  inventoryId?: string | null;
+
+  @Column({ name: 'performed_by', type: 'varchar', length: 120, nullable: true })
+  performedBy?: string | null;
+
+  @Column({ name: 'occurred_at', type: 'timestamptz', default: () => 'now()' })
+  occurredAt!: Date;
+}