add yard distances management to rule engine

- Introduced new yard distances resource with CRUD operations.
- Created migration for yard distances table with necessary constraints.
- Implemented service and repository for yard distances handling.
- Added controller for API endpoints to manage yard distances.
- Updated rule engine configuration to include yard distances.
- Enhanced rule engine resource page to support yard distance selection.
- Updated contracts and train builder pages to handle new yard distance logic.
- Added error handling utility for better error message extraction.

apps/edr-freight-web/backoffice/src/services/contracts.service.ts

@@ -229,15 +229,26 @@ export const contractsService = {
   approveStep: ({ id, stepId }: { id: string; stepId: string }) =>
     postContract<Freight.IContract>(C.APPROVE_STEP(id, stepId)),
 
+  /**
+   * Reject the current step. Without `returnToStepId` the contract is rejected
+   * to the customer (terminal). With it, the contract is sent back to that
+   * earlier approved step and the chain re-runs from there.
+   */
   rejectStep: ({
     id,
     stepId,
     reason,
+    returnToStepId,
   }: {
     id: string;
     stepId: string;
     reason: string;
-  }) => postContract<Freight.IContract>(C.REJECT_STEP(id, stepId), { reason }),
+    returnToStepId?: string;
+  }) =>
+    postContract<Freight.IContract>(C.REJECT_STEP(id, stepId), {
+      reason,
+      ...(returnToStepId ? { returnToStepId } : {}),
+    }),
 
   // ── Contract document ──
   generateContract: (id: string) =>

apps/edr-freight-web/backoffice/src/services/locomotives.service.ts

@@ -15,6 +15,10 @@ export type LocomotiveStatus =
 export interface LocomotiveListFilters {
   status?: LocomotiveStatus;
   currentYardId?: string;
+  /** Drop locos already coupled to a built train (train-builder picker). */
+  excludeCoupled?: boolean;
+  /** With excludeCoupled: keep THIS train's own coupled locos in the list. */
+  excludeTrainId?: string;
 }
 
 export interface Locomotive {
@@ -48,6 +52,8 @@ export const locomotivesService = {
     const params = new URLSearchParams();
     if (filters.status) params.set('status', filters.status);
     if (filters.currentYardId) params.set('currentYardId', filters.currentYardId);
+    if (filters.excludeCoupled) params.set('excludeCoupled', 'true');
+    if (filters.excludeTrainId) params.set('excludeTrainId', filters.excludeTrainId);
     const qs = params.toString();
     return apiClient.get<Locomotive[]>(
       `${URL_CONSTANTS.LOCOMOTIVES.BASE}${qs ? `?${qs}` : ''}`,

apps/edr-freight-web/backoffice/src/services/routes.service.ts

@@ -35,8 +35,9 @@ export interface RouteRecord {
   milestones?: RouteMilestone[];
 }
 
+/** Segment km are resolved server-side from configured yard distances. */
 export interface SaveRoutePayload {
-  milestones: Array<{ yardId: string; distanceKm?: number }>;
+  milestones: Array<{ yardId: string }>;
   status?: RouteStatus;
 }
 

apps/edr-freight-web/backoffice/src/services/ruleEngine/ruleEngine.service.ts

@@ -86,6 +86,7 @@ const RESOURCE_BASE: Record<RuleEngineResourceSlug, string> = {
   "service-types": URL_CONSTANTS.RULE_ENGINE.SERVICE_TYPES,
   "weight-limit-rules": URL_CONSTANTS.RULE_ENGINE.WEIGHT_LIMIT_RULES,
   yards: URL_CONSTANTS.RULE_ENGINE.YARDS,
+  "yard-distances": URL_CONSTANTS.RULE_ENGINE.YARD_DISTANCES,
   "shipping-lines": URL_CONSTANTS.RULE_ENGINE.SHIPPING_LINES,
   rates: URL_CONSTANTS.RULE_ENGINE.RATES,
   "approval-rules": URL_CONSTANTS.RULE_ENGINE.APPROVAL_RULES,
@@ -107,6 +108,8 @@ const byIdPath = (resource: RuleEngineResourceSlug, id: string): string => {
       return URL_CONSTANTS.RULE_ENGINE.WEIGHT_LIMIT_RULE_BY_ID(id);
     case "yards":
       return URL_CONSTANTS.RULE_ENGINE.YARD_BY_ID(id);
+    case "yard-distances":
+      return URL_CONSTANTS.RULE_ENGINE.YARD_DISTANCE_BY_ID(id);
     case "shipping-lines":
       return URL_CONSTANTS.RULE_ENGINE.SHIPPING_LINE_BY_ID(id);
     case "rates":