Enhance wagon capacity handling and validation in booking service

- Added default capacities for container and bulk wagons.
- Updated wagonsFor method to consider weight and length for wagon calculations.
- Improved handling of overweight bookings with appropriate warnings.
- Adjusted tests to reflect changes in wagon capacity and validation logic.

apps/edr-freight-api/src/modules/train-scheduling/train-scheduling.service.ts

@@ -2802,10 +2802,14 @@ export class TrainSchedulingService {
             `Booking ${booking.reference} is within the soft hold window (expires ${booking.holdExpiresAt?.toISOString()})`,
           );
         }
+        // Overweight is the soft threshold (maxVgmTons): the customer already
+        // paid the overweight surcharge at booking. The hard ceiling
+        // (maxCapacityTons) blocks booking creation, so anything reaching
+        // scheduling is shippable — warn the planner, never block allocation.
         const overweightLines = (booking.bookingContainers ?? []).filter((c) => c.isOverweight);
         if (overweightLines.length) {
-          violations.push(
-            `Booking ${booking.reference} has overweight container lines; use forceAssign to override`,
+          warnings.push(
+            `Booking ${booking.reference} has ${overweightLines.length} overweight container line(s); overweight surcharge applied`,
           );
         }
       }