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/migrations/3660000000000-SchedulePlannedWagonCouples.ts

@@ -0,0 +1,37 @@
+import { MigrationInterface, QueryRunner } from 'typeorm';
+
+/**
+ * Per-schedule consist-change plan, executed automatically as the trip
+ * proceeds (dispatch / checkpoint logs):
+ *
+ * - `planned_wagon_couples` `{ wagonId: pickupYardId }` — LOOSE wagons this
+ *   departure couples onto the train at a route stop. They join the built
+ *   train permanently when the train reaches that stop.
+ * - `planned_wagon_real_cuts` `[wagonId, ...]` — cut wagons (see
+ *   planned_wagon_cut_yards) flagged as REAL cuts: the built train
+ *   permanently loses the wagon at its cut yard, instead of the default
+ *   soft cut where it stays in the build and only sits out this trip.
+ */
+export class SchedulePlannedWagonCouples3660000000000 implements MigrationInterface {
+  name = 'SchedulePlannedWagonCouples3660000000000';
+
+  public async up(queryRunner: QueryRunner): Promise<void> {
+    await queryRunner.query(`
+      ALTER TABLE freight.train_schedules
+        ADD COLUMN IF NOT EXISTS planned_wagon_couples jsonb
+    `);
+    await queryRunner.query(`
+      ALTER TABLE freight.train_schedules
+        ADD COLUMN IF NOT EXISTS planned_wagon_real_cuts jsonb
+    `);
+  }
+
+  public async down(queryRunner: QueryRunner): Promise<void> {
+    await queryRunner.query(`
+      ALTER TABLE freight.train_schedules DROP COLUMN IF EXISTS planned_wagon_couples
+    `);
+    await queryRunner.query(`
+      ALTER TABLE freight.train_schedules DROP COLUMN IF EXISTS planned_wagon_real_cuts
+    `);
+  }
+}