Fix:

Added assertCapacity() checks before saving (matches single receive)
Added applyCapacityDelta() after save to increment counters
Now validates warehouse → yard → zone capacity hierarchy
Single receive already had both checks; bulk receive was gap.

apps/edr-freight-api/src/modules/maintenance/maintenance.service.ts

@@ -1,14 +1,19 @@
-import { Injectable } from '@nestjs/common';
+import { Injectable, Logger } from '@nestjs/common';
 import { InjectRepository } from '@nestjs/typeorm';
+import { Cron, CronExpression } from '@nestjs/schedule';
+import { NotificationAudience, NotificationType } from '@edr/types';
 import { DataSource, Repository } from 'typeorm';
 import { MaintenanceRepository } from './maintenance.repository';
 import { MaintenanceSchedule, MaintenanceStatus } from './entities/maintenance-schedule.entity';
 import { MaintenanceCost } from './entities/maintenance-cost.entity';
 import { Vehicle, VehicleAvailability, VehicleStatus } from '../vehicles/entities/vehicle.entity';
 import { CreateMaintenanceScheduleDto, CreateMaintenanceCostDto, UpdateMaintenanceScheduleDto } from './dto/create-maintenance.dto';
+import { NotificationInboxService } from '../notification-inbox/notification-inbox.service';
 
 @Injectable()
 export class MaintenanceService {
+  private readonly logger = new Logger(MaintenanceService.name);
+
   constructor(
     private readonly maintenanceRepository: MaintenanceRepository,
     @InjectRepository(MaintenanceSchedule)
@@ -18,8 +23,44 @@ export class MaintenanceService {
     // Vehicle isn't registered in this module's TypeOrmModule.forFeature, so we
     // reach it through the global DataSource rather than @InjectRepository.
     private readonly dataSource: DataSource,
+    private readonly inbox: NotificationInboxService,
   ) {}
 
+  /** Fleet-wide next-due board — see MaintenanceRepository.getDueBoard. */
+  async getDueBoard() {
+    return this.maintenanceRepository.getDueBoard();
+  }
+
+  /**
+   * Daily check: a vehicle's driven km (latest fuel-up odometer reading, since
+   * that's the only place mileage is actually recorded) or its due date has
+   * reached a SCHEDULED item's threshold → alert backoffice once.
+   */
+  @Cron(CronExpression.EVERY_DAY_AT_7AM, { name: 'maintenance-due-alert' })
+  async sendDueAlerts(): Promise<void> {
+    try {
+      const due = await this.maintenanceRepository.getUnnotifiedDue();
+      for (const item of due) {
+        const reason =
+          item.nextDueKm != null && (item.currentKm ?? 0) >= item.nextDueKm
+            ? `driven ${item.currentKm} km (due at ${item.nextDueKm} km)`
+            : `due ${new Date(item.nextDueDate as Date).toLocaleDateString()}`;
+        await this.inbox.notify({
+          recipients: { allBackoffice: true },
+          audience: NotificationAudience.BACKOFFICE,
+          type: NotificationType.GENERIC,
+          title: `Maintenance due — ${item.plateNumber}`,
+          body: `${item.plateNumber} (${item.maintenanceType}) is due for maintenance — ${reason}. ${item.description}`,
+          link: `/dashboard/maintenance?vehicleId=${item.vehicleId}`,
+          data: { vehicleId: item.vehicleId, scheduleId: item.id, action: 'MAINTENANCE_DUE' },
+        });
+        await this.scheduleRepository.update(item.id, { dueNotifiedAt: new Date() });
+      }
+    } catch (err) {
+      this.logger.error(`sendDueAlerts failed: ${(err as Error).message}`, (err as Error).stack);
+    }
+  }
+
   /**
    * Reflect a maintenance schedule's lifecycle on the target vehicle. A vehicle
    * under maintenance is taken out of service (MAINTENANCE + BUSY); once the