fix(warehouse): scope the arrival GRN stamp to EXPORT only

The previous commit made autoUnloadArrived and unloadBooking raise a GRN for any
direction, which changed import behaviour. Import keeps its own GRN handling
(autoUnloadArrivedBookings) and is left exactly as it was. Both paths now stamp a
GRN only when the booking is EXPORT — the direction whose cargo needs one to be
loaded onto a train. Import and domestic behave as before.

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

apps/edr-freight-api/src/modules/warehouses/warehouse-inventory.service.ts

@@ -1032,8 +1032,8 @@ export class WarehouseInventoryService {
           result.results.push({ bookingId: booking.id, status: 'FAILED', reason: 'No warehouse/yard/zone configured' });
           continue;
         }
-        // Goods reaching the warehouse always get a GRN, whichever path brought
+        // EXPORT goods get their GRN on arrival at the warehouse — nothing loads
-        // them in — nothing loads onto a train without one.
+        // onto a train without one. Import GRN handling is left untouched.
         const saved = await this.inventoryRepository.create({
           warehouseId: location.warehouseId,
           yardId: location.yardId,
@@ -1043,11 +1043,9 @@ export class WarehouseInventoryService {
           weight: Number(booking.weight) || 0,
           status: 'RECEIVED',
           arrivedAt: new Date(),
-          grnNumber: this.generateGrnNumber(
+          ...(booking.tradeDirection === 'EXPORT'
-            booking.tradeDirection ?? 'WH',
+            ? { grnNumber: this.generateGrnNumber('EXPORT', booking.id, new Date()) }
-            booking.id,
+            : {}),
-            new Date(),
-          ),
           notes: allocated?.rule ? `Auto-unloaded → ${allocated.path}` : 'Auto-unloaded from arrival queue',
         });
         result.processedCount += 1;
@@ -1068,14 +1066,14 @@ export class WarehouseInventoryService {
   /** Unload a single arrived booking into a chosen (or default) location. */
   async unloadBooking(bookingId: string, dto: UnloadBookingDto): Promise<WarehouseInventory> {
     const existing = await this.inventoryRepository.findAll({ where: { bookingId } });
-    // Goods reaching the warehouse always get a GRN, whichever path brought them
+    // EXPORT goods get their GRN on arrival at the warehouse — nothing loads onto
-    // in — nothing loads onto a train without one.
+    // a train without one. Import GRN handling is left untouched.
     const [bookingRow]: Array<{ tradeDirection: string | null }> = await this.dataSource.query(
       `SELECT trade_direction AS "tradeDirection"
          FROM freight.bookings WHERE id = $1 AND deleted_at IS NULL`,
       [bookingId],
     );
-    const grnDirection = bookingRow?.tradeDirection ?? 'WH';
+    const isExport = bookingRow?.tradeDirection === 'EXPORT';
 
     let location: DefaultLocation | null =
       dto.warehouseId && dto.yardId && dto.zoneId
@@ -1096,10 +1094,10 @@ export class WarehouseInventoryService {
         zoneId: location.zoneId,
         status: 'RECEIVED',
         arrivedAt,
-        // Keep an already-issued GRN; only raise one if this row never got it.
+        // Export only, and keep an already-issued GRN rather than reissuing.
-        ...(existing[0].grnNumber
+        ...(isExport && !existing[0].grnNumber
-          ? {}
+          ? { grnNumber: this.generateGrnNumber('EXPORT', bookingId, arrivedAt) }
-          : { grnNumber: this.generateGrnNumber(grnDirection, bookingId, arrivedAt) }),
+          : {}),
         notes: dto.notes ?? existing[0].notes ?? 'Unloaded',
       });
       return this.findById(existing[0].id);
@@ -1114,7 +1112,9 @@ export class WarehouseInventoryService {
       weight: 0,
       status: 'RECEIVED',
       arrivedAt,
-      grnNumber: this.generateGrnNumber(grnDirection, bookingId, arrivedAt),
+      ...(isExport
+        ? { grnNumber: this.generateGrnNumber('EXPORT', bookingId, arrivedAt) }
+        : {}),
       notes: dto.notes ?? 'Unloaded',
     });
     return this.findById(saved.id);