feat: add contract extension request functionality

- Implemented  method in  to allow customers to request an extension for expired contracts.
- Added  component in  for users to initiate extension requests.
- Updated  to include logic for handling extension requests for expired contracts.
- Enhanced  to display extension request options and status.
- Created migration to add  and  columns to the contracts table.
- Added unit tests for contract extension request and handling in .
- Defined DTOs for request and extension in .
- Updated types in  to include new fields related to contract extensions.

apps/edr-freight-api/src/modules/train-scheduling/utils/wagon-plan.util.ts

@@ -20,12 +20,17 @@ export type TrainLimitConfig = {
   maxWeightTons?: number;
   maxLengthMeters?: number;
   maxWagonsPerTrain?: number;
-  max20ftContainerWeightTons?: number;
   max20ftPairWeightDiffTons?: number;
 };
 
 export type ContainerPlacementRules = {
-  max20ftContainerWeightTons?: number;
+  /**
+   * Hard per-box weight ceiling keyed by booking container LINE id, resolved
+   * from the rule engine's weight limit rule (`max_capacity_tons`) for the
+   * line's container type and the booking's trade direction. A line with no
+   * entry has no ceiling — the rule's capacity is optional.
+   */
+  maxContainerWeightTonsByLineId?: Record<string, number>;
   max20ftPairWeightDiffTons?: number;
 };
 
@@ -820,15 +825,21 @@ export function perEdgeConsistUsage(
   );
 }
 
+/**
+ * Per-box weight rules for a container plan:
+ *  - every unit is checked against its line's weight-limit-rule capacity
+ *    ceiling (`maxContainerWeightTonsByLineId`, any size);
+ *  - 20ft pairs sharing a wagon are checked for weight imbalance.
+ */
 export function validate20ftContainerRules(
   units: ContainerUnitRow[],
   placements: ContainerPlacementInput[],
   rules?: ContainerPlacementRules,
 ): string[] {
   const violations: string[] = [];
-  const maxEach = rules?.max20ftContainerWeightTons;
+  const capacityByLine = rules?.maxContainerWeightTonsByLineId;
   const maxDiff = rules?.max20ftPairWeightDiffTons;
-  if (maxEach == null && maxDiff == null) return violations;
+  if (capacityByLine == null && maxDiff == null) return violations;
 
   const placementByUnit = new Map(
     placements.map((p) => [`${p.bookingContainerId}:${p.unitIndex}`, p]),
@@ -837,15 +848,16 @@ export function validate20ftContainerRules(
   const weightsBySlot = new Map<number, number[]>();
 
   for (const unit of units) {
-    const sizeFt = unit.sizeFt ?? (unit.containerTypeCode.includes('40') ? 40 : 20);
-    if (sizeFt >= 40) continue;
-
+    const maxEach = capacityByLine?.[unit.bookingContainerId];
     if (maxEach != null && unit.grossWeightTons > maxEach) {
       violations.push(
-        `${unit.label} weight ${unit.grossWeightTons}T exceeds max ${maxEach}T for 20ft containers`,
+        `${unit.label} weight ${unit.grossWeightTons}T exceeds the weight limit rule capacity of ${maxEach}T for ${unit.containerTypeCode} containers`,
       );
     }
 
+    const sizeFt = unit.sizeFt ?? (unit.containerTypeCode.includes('40') ? 40 : 20);
+    if (sizeFt >= 40) continue;
+
     const placement = placementByUnit.get(`${unit.bookingContainerId}:${unit.unitIndex}`);
     if (!placement?.sequenceNo) continue;