feat: implement 20ft container weight-pairing validation

- Added ContainerValidationService to handle 20ft weight-pairing logic.
- Introduced validate20ftWeightPairing utility function to check weight differences.
- Updated BookingPricingService to include overweight line details and pairing errors in price response.
- Enhanced BookingTransitionService to reject submissions with unpairable 20ft containers.
- Created ShipmentValidation interface for pre-submit validation of container contracts.
- Integrated shipment validation into the contract booking process, providing warnings for overweight containers and hard blocks for pairing errors.
- Updated front-end components to display validation results and prevent submission when errors are present.

apps/edr-freight-api/src/modules/bookings/booking-pricing.service.spec.ts

@@ -45,6 +45,7 @@ describe('BookingPricingService — domestic corridor', () => {
       {} as never,
       ratesService as never,
       exchangeService as never,
+      { validate20ftPairing: jest.fn().mockResolvedValue([]) } as never,
     );
   });