Add migration to repair schema drift and implement contract step banner in UI

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

@@ -103,6 +103,7 @@ import {
 import {
   computeExportWindowTimes,
   computeImportWindowTimes,
+  earliestSchedulableDeparture,
   eatDay,
 } from './batch-window.util';
 import { TrainCheckpointEvent } from './entities/train-checkpoint-event.entity';
@@ -469,6 +470,23 @@ export class TrainSchedulingService {
       // (opens at 08:00 EAT `importWindowLeadDays` before departure); EXPORT opens
       // 24h before departure (FCFS). No schedule is ever always-open now.
       const windowCfg = await this.getWindowConfig();
+
+      // Staff cannot schedule inside the lead window — there must be room for a
+      // booking window before departure. IMPORT/DOMESTIC lead is in whole EAT
+      // days (lead 3, today 11th → first allowed departure is the 14th); EXPORT
+      // lead is in hours (24h = 1 day ahead).
+      const earliest = earliestSchedulableDeparture(direction, windowCfg, new Date());
+      if (departure.getTime() < earliest.getTime()) {
+        const detail =
+          direction === 'EXPORT'
+            ? `at least ${windowCfg.exportBookingLeadHours} hour(s) ahead`
+            : `at least ${windowCfg.importWindowLeadDays} day(s) ahead`;
+        throw new BadRequestException(
+          `Departure ${departure.toISOString()} is inside the booking lead window; ` +
+            `${direction === 'EXPORT' ? 'export' : 'import'} trains must be scheduled ${detail} ` +
+            `(earliest ${earliest.toISOString()})`,
+        );
+      }
       const windowFields =
         direction === 'EXPORT'
           ? {