feat(train-scheduling): mid-route consist changes, audit history, safer workspace

- planned couples: loose wagons join the train at a route stop, added
  from the schedule yards tab; capacity credits them per corridor edge
  and coupling validates locomotive weight/length caps per leg
- real-cut toggle: a cut wagon permanently leaves the train build at
  its cut yard (soft cut still sits out one trip only)
- fix heaviest-leg display counting a shared slot's full cargo on
  every spanned edge (phantom pull-weight overload on S-2026-00045)
- confirmation dialogs for workspace add/load/unload/remove actions
- train-builder History and Detached-wagons tabs, backed by paginated
  endpoints; builder detaches now always write adjustment-log rows

Migrations 3660 (planned_wagon_couples, planned_wagon_real_cuts) and
3670 (adjustment log train_schedule_id nullable) — both applied to the
dev DB by hand; watch mode does not run migrations.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

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

@@ -14,6 +14,7 @@ import {
   sumWagonsRequired,
   validate20ftContainerRules,
   validateContainerPlacements,
+  validateMixedTrainLimitsPerEdge,
   validateWagonCargoExclusivity,
 } from './wagon-plan.util';
 
@@ -412,4 +413,91 @@ describe('maxEdgeConsistUsage — the binding edge, not the whole-route sum', ()
       loadedWagonCount: 2,
     });
   });
+
+  it('with a legs map, shared-slot cargo weighs only its own edges (the S-2026-00045 shape)', () => {
+    // One wagon reused across legs: booking X rides a→b (40T), booking Y
+    // boards at b with 30T. The slot spans the whole route, but edge a→b
+    // must weigh 24 + 40 = 64T — not 24 + 70. Tare rides both edges.
+    const shared = {
+      tareWeightTons: 24,
+      assignedWeightTons: 70,
+      lengthMeters: 14,
+      boardYardId: null,
+      alightYardId: null,
+      allocations: [
+        { bookingId: 'X', allocatedWeightTons: 40 },
+        { bookingId: 'Y', allocatedWeightTons: 30 },
+      ],
+    } as never;
+    const legs = new Map([
+      ['X', { from: 0, to: 1 }],
+      ['Y', { from: 1, to: 2 }],
+    ]);
+    // Without legs: whole-span scalar on both edges (94T binding edge).
+    expect(maxEdgeConsistUsage([shared], stops).grossWeightTons).toBe(94);
+    // With legs: heaviest edge is a→b at 64T (b→c is 54T).
+    expect(maxEdgeConsistUsage([shared], stops, legs).grossWeightTons).toBe(64);
+  });
+
+  it('falls back to the whole-span scalar when an allocation has no readable weight', () => {
+    const shared = {
+      tareWeightTons: 24,
+      assignedWeightTons: 70,
+      lengthMeters: 14,
+      boardYardId: null,
+      alightYardId: null,
+      allocations: [{ bookingId: 'X' }],
+    } as never;
+    const legs = new Map([['X', { from: 0, to: 1 }]]);
+    expect(maxEdgeConsistUsage([shared], stops, legs).grossWeightTons).toBe(94);
+  });
+});
+
+describe('validateMixedTrainLimitsPerEdge — leg-aware cargo weighing', () => {
+  it('does not flag a leg whose overweight is only later-boarding cargo (S-2026-00045)', () => {
+    // 2 shared wagons, 100T cap. Booking X rides a→b with 30T/wagon, booking Y
+    // boards at b with 25T/wagon. Whole-span scalars read every edge as
+    // 2×(20 + 55) = 150T > 100T; the cargo actually aboard is 100T (a→b) and
+    // 90T (b→c) — both fit.
+    const slot = (seq: number) => ({
+      sequenceNo: seq,
+      wagonTypeId: 'wt-nw5',
+      wagonTypeCode: 'NW5',
+      capacityTons: 70,
+      lengthMeters: 14,
+      tareWeightTons: 20,
+      assignedWeightTons: 55,
+      boardYardId: null,
+      alightYardId: null,
+      allocations: [
+        {
+          bookingId: 'X',
+          bookingReference: 'X',
+          allocatedWeightTons: 30,
+          loadType: AllocationLoadType.Container,
+        },
+        {
+          bookingId: 'Y',
+          bookingReference: 'Y',
+          allocatedWeightTons: 25,
+          loadType: AllocationLoadType.Container,
+        },
+      ],
+    });
+    const legs = new Map([
+      ['X', { from: 0, to: 1 }],
+      ['Y', { from: 1, to: 2 }],
+    ]);
+    const run = (withLegs?: typeof legs) =>
+      validateMixedTrainLimitsPerEdge(
+        [slot(1), slot(2)] as never,
+        [{ lengthMeters: 14 }],
+        { maxWeightTons: 100 },
+        ['a', 'b', 'c'],
+        undefined,
+        withLegs,
+      );
+    expect(run()).toHaveLength(2); // both edges falsely overweight without legs
+    expect(run(legs)).toHaveLength(0);
+  });
 });

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

@@ -654,9 +654,16 @@ export function validateMixedTrainLimitsPerEdge(
   const label = (i: number) => stopLabels?.[i] ?? stops[i];
   const violations = new Set<string>();
   for (let edge = 0; edge < stops.length - 1; edge += 1) {
-    const active = wagonPlan.filter(
-      (_, i) => spans[i].from <= edge && edge < spans[i].to,
-    );
+    // A shared slot rides the UNION of its cargo legs, but only carries each
+    // booking's cargo on that booking's own edges — weigh the edge with the
+    // cargo actually aboard there, not the slot's whole-route scalar, or a
+    // container boarding at Dire Dawa reads as hauled from Djibouti.
+    const active = wagonPlan
+      .filter((_, i) => spans[i].from <= edge && edge < spans[i].to)
+      .map((slot) => ({
+        ...slot,
+        assignedWeightTons: slotCargoOnEdge(slot, edge, edges, legs),
+      }));
     if (!active.length) continue;
     for (const violation of validateMixedTrainLimits(
       active,
@@ -684,6 +691,40 @@ export type EdgeUsageSlot = Pick<
   allocations?: unknown[];
 };
 
+/**
+ * Cargo tons a slot actually carries on one edge. With a legs map and readable
+ * allocation records, each booking's cargo counts only on the edges that
+ * booking rides (an unmapped booking stays on the slot's whole span). Without
+ * either — or when any allocation lacks a numeric weight, e.g. persisted rows
+ * fed through {@link EdgeUsageSlot} — falls back to the slot's whole-span
+ * `assignedWeightTons`, the pre-existing reading.
+ */
+function slotCargoOnEdge(
+  slot: EdgeUsageSlot,
+  edge: number,
+  edgeCount: number,
+  legs?: Map<string, { from: number; to: number }>,
+): number {
+  const wholeSpanCargo = Number(slot.assignedWeightTons ?? 0);
+  const allocations = (slot.allocations ?? []) as Array<{
+    bookingId?: string;
+    allocatedWeightTons?: number | string;
+  }>;
+  if (!legs?.size || !allocations.length) return wholeSpanCargo;
+  let cargo = 0;
+  for (const allocation of allocations) {
+    const weight = Number(allocation?.allocatedWeightTons);
+    if (!Number.isFinite(weight)) return wholeSpanCargo;
+    const leg = allocation.bookingId ? legs.get(allocation.bookingId) : undefined;
+    const rides =
+      !leg || leg.from < 0 || leg.to > edgeCount || leg.from >= leg.to
+        ? true
+        : leg.from <= edge && edge < leg.to;
+    if (rides) cargo += weight;
+  }
+  return cargo;
+}
+
 /** Per-slot stop-index spans; a yard missing from the stop list keeps the slot on the whole route. */
 function slotSpans(
   wagonPlan: EdgeUsageSlot[],
@@ -708,8 +749,10 @@ function slotSpans(
 export function maxEdgeConsistUsage(
   wagonPlan: EdgeUsageSlot[],
   stops: string[],
+  /** Booking id → stop-index span; cargo then weighs only its own edges. */
+  legs?: Map<string, { from: number; to: number }>,
 ): { grossWeightTons: number; lengthMeters: number; loadedWagonCount: number } {
-  return perEdgeConsistUsage(wagonPlan, stops).reduce(
+  return perEdgeConsistUsage(wagonPlan, stops, legs).reduce(
     (max, e) => ({
       grossWeightTons: Math.max(max.grossWeightTons, e.grossWeightTons),
       lengthMeters: Math.max(max.lengthMeters, e.lengthMeters),
@@ -737,12 +780,19 @@ export type EdgeConsistUsage = {
 export function perEdgeConsistUsage(
   wagonPlan: EdgeUsageSlot[],
   stops: string[],
+  /**
+   * Booking id → stop-index span. When given, a shared slot's cargo weighs
+   * only the edges its booking rides (tare still rides the slot's whole
+   * span) — without it a slot's full cargo counts on every edge it spans.
+   */
+  legs?: Map<string, { from: number; to: number }>,
 ): EdgeConsistUsage[] {
+  const edgeCount = Math.max(1, stops.length - 1);
   const totals = (edge: number, slots: EdgeUsageSlot[]): EdgeConsistUsage => ({
     edge,
     grossWeightTons: slots.reduce(
       (sum, w) =>
-        sum + Number(w.tareWeightTons ?? 0) + Number(w.assignedWeightTons ?? 0),
+        sum + Number(w.tareWeightTons ?? 0) + slotCargoOnEdge(w, edge, edgeCount, legs),
       0,
     ),
     lengthMeters: slots.reduce((sum, w) => sum + Number(w.lengthMeters ?? 0), 0),