feat: enhance train scheduling and contract management features

- Added StationWorkControls to manage loading/unloading phases in TrainScheduleV2DetailPage.
- Implemented API endpoints for recording station work and managing wagon detach requests.
- Updated contract templates to include Ethiopian customs handling options.
- Enhanced shipment forms to collect customs clearing agent details for without-customs bookings.
- Introduced NUMBER_OF_WAGONS as a unit of measure for bulk cargo, allowing customers to specify wagon counts.
- Improved validation for customs clearing agent information in shipment forms.
- Updated various components and services to accommodate new features and ensure data integrity.

apps/edr-freight-api/src/modules/rule-engine/entities/rate-unit.util.ts

@@ -1,7 +1,12 @@
 import type { RateAppliesTo, RateTrigger, RateUnit } from './rate.entity';
 
-/** How the bulk commodity a rate is scoped to is counted (cargo_types.unit_of_measure). */
-export type CargoUom = 'PER_TON' | 'PER_ITEM' | null | undefined;
+/**
+ * How the bulk commodity a rate is scoped to is counted
+ * (cargo_types.unit_of_measure). NUMBER_OF_WAGONS cargo is weighed in tons and
+ * offers the same PER_TON / PER_WAGON units as PER_TON cargo — only the
+ * booking form (which also asks for a wagon count) treats it differently.
+ */
+export type CargoUom = 'PER_TON' | 'PER_ITEM' | 'NUMBER_OF_WAGONS' | null | undefined;
 
 /**
  * Units billed against a booking's bulk quantity. That quantity is recorded in