feat(warehouses): record container vs bulk freight type

Nullable freight_type on the warehouse, null meaning it takes both.
No backfill: every existing warehouse is unrestricted today and
writing a value would narrow allocation behind the operator's back.
Reuses FREIGHT_TYPES from the booking entity rather than a third copy
of the same two values.

apps/edr-freight-api/src/migrations/3820000000000-WarehouseFreightType.ts

@@ -0,0 +1,21 @@
+import { MigrationInterface, QueryRunner } from 'typeorm';
+
+/**
+ * `freight.warehouses.freight_type` — CONTAINER or BULK, or null for a site
+ * that takes both.
+ *
+ * Nullable with no backfill on purpose: every existing warehouse predates the
+ * field and is unrestricted today, so writing a value would narrow live
+ * allocation behind the operator's back.
+ */
+export class WarehouseFreightType3820000000000 implements MigrationInterface {
+  public async up(queryRunner: QueryRunner): Promise<void> {
+    await queryRunner.query(
+      `ALTER TABLE freight.warehouses ADD COLUMN IF NOT EXISTS freight_type varchar(16)`,
+    );
+  }
+
+  public async down(queryRunner: QueryRunner): Promise<void> {
+    await queryRunner.query(`ALTER TABLE freight.warehouses DROP COLUMN IF EXISTS freight_type`);
+  }
+}