Enhance bulk booking handling and wagon capacity calculations across services

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

@@ -55,12 +55,17 @@ export class BookingSplitService {
    * Size the largest part of the booking that fits `freeWagons`, priced via an
    * in-memory clone. Returns null when nothing meaningful fits (no whole
    * container unit / no bulk tonnage, or pricing failed).
+   *
+   * `maxOfferedWeightTons` caps the offered CARGO tonnage (bulk only) — on a
+   * weight-limited train the wagons' own tare eats into the locomotive's
+   * remaining pull weight, so the caller passes the room left after tare.
    */
   async sizeOffer(
     booking: Booking,
     freeWagons: number,
     totalWagons: number,
     bulkWagonCapacityTons: number,
+    maxOfferedWeightTons?: number,
   ): Promise<SizedOffer | null> {
     if (freeWagons < 1 || freeWagons >= totalWagons) return null;
 
@@ -110,10 +115,15 @@ export class BookingSplitService {
       if (!offeredLines.length || offeredWagons <= 0) return null;
       clone.bookingContainers = clonedContainers;
     } else {
-      // Bulk: split by weight — the offered part is what freeWagons can carry.
+      // Bulk: split by weight — the offered part is what freeWagons can carry,
+      // further capped by the caller's weight room when the pull limit binds.
       const totalWeight = Number(booking.cargoTotalWeightVgm ?? 0);
       if (totalWeight <= 0 || bulkWagonCapacityTons <= 0) return null;
-      offeredWeightTons = Math.min(totalWeight, freeWagons * bulkWagonCapacityTons);
+      offeredWeightTons = Math.min(
+        totalWeight,
+        freeWagons * bulkWagonCapacityTons,
+        maxOfferedWeightTons ?? Number.POSITIVE_INFINITY,
+      );
       if (offeredWeightTons <= 0) return null;
       offeredWagons = Math.min(
         freeWagons,