feat: add maintenance tracking module foundation

Entities:
- MaintenanceSchedule: track preventive/corrective maintenance
- MaintenanceCost: record actual maintenance expenses

DTOs:
- CreateMaintenanceScheduleDto: schedule maintenance
- CreateMaintenanceCostDto: log costs
- UpdateMaintenanceScheduleDto: mark complete/adjust cost

Repository:
- getUpcomingMaintenance(): find due maintenance
- getMaintenanceCosts(): historical costs by date
- getTotalMaintenanceCost(): aggregate spending

Also fixed fuel-consumption.entity.ts: totalDistanceKm default 0

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

apps/edr-freight-api/src/modules/maintenance/entities/maintenance-cost.entity.ts

@@ -0,0 +1,43 @@
+import { BaseEntity } from '@edr/api-common';
+import { Entity, Column, ManyToOne, JoinColumn, Index } from 'typeorm';
+import { Vehicle } from '../../vehicles/entities/vehicle.entity';
+import { MaintenanceSchedule } from './maintenance-schedule.entity';
+
+@Entity({ name: 'maintenance_costs', schema: 'freight' })
+@Index(['vehicleId', 'incurredDate'])
+export class MaintenanceCost extends BaseEntity {
+  @Column({ name: 'vehicle_id', type: 'uuid' })
+  vehicleId!: string;
+
+  @ManyToOne(() => Vehicle, { eager: false })
+  @JoinColumn({ name: 'vehicle_id' })
+  vehicle!: Vehicle;
+
+  @Column({ name: 'maintenance_schedule_id', type: 'uuid', nullable: true })
+  maintenanceScheduleId?: string;
+
+  @ManyToOne(() => MaintenanceSchedule, { eager: false, onDelete: 'SET NULL' })
+  @JoinColumn({ name: 'maintenance_schedule_id' })
+  maintenanceSchedule?: MaintenanceSchedule;
+
+  @Column({ name: 'incurred_date', type: 'timestamptz' })
+  incurredDate!: Date;
+
+  @Column({ name: 'cost_amount', type: 'numeric', precision: 14, scale: 2 })
+  costAmount!: number;
+
+  @Column({ name: 'cost_type' })
+  costType!: string; // 'PARTS', 'LABOR', 'DIAGNOSTICS', 'OTHER'
+
+  @Column({ name: 'description' })
+  description!: string;
+
+  @Column({ name: 'service_provider', nullable: true })
+  serviceProvider?: string;
+
+  @Column({ name: 'invoice_number', nullable: true })
+  invoiceNumber?: string;
+
+  @Column({ type: 'text', nullable: true })
+  notes?: string;
+}

apps/edr-freight-api/src/modules/maintenance/entities/maintenance-schedule.entity.ts

@@ -0,0 +1,65 @@
+import { BaseEntity } from '@edr/api-common';
+import { Entity, Column, ManyToOne, JoinColumn, Index } from 'typeorm';
+import { Vehicle } from '../../vehicles/entities/vehicle.entity';
+
+export enum MaintenanceType {
+  PREVENTIVE = 'PREVENTIVE',
+  CORRECTIVE = 'CORRECTIVE',
+  INSPECTION = 'INSPECTION',
+  REPAIR = 'REPAIR',
+}
+
+export enum MaintenanceStatus {
+  SCHEDULED = 'SCHEDULED',
+  IN_PROGRESS = 'IN_PROGRESS',
+  COMPLETED = 'COMPLETED',
+  CANCELLED = 'CANCELLED',
+  OVERDUE = 'OVERDUE',
+}
+
+@Entity({ name: 'maintenance_schedules', schema: 'freight' })
+@Index(['vehicleId', 'scheduledDate'])
+export class MaintenanceSchedule extends BaseEntity {
+  @Column({ name: 'vehicle_id', type: 'uuid' })
+  vehicleId!: string;
+
+  @ManyToOne(() => Vehicle, { eager: false })
+  @JoinColumn({ name: 'vehicle_id' })
+  vehicle!: Vehicle;
+
+  @Column({ name: 'maintenance_type', type: 'varchar' })
+  maintenanceType!: MaintenanceType;
+
+  @Column({ name: 'description' })
+  description!: string;
+
+  @Column({ name: 'scheduled_date', type: 'timestamptz' })
+  scheduledDate!: Date;
+
+  @Column({ name: 'completed_date', type: 'timestamptz', nullable: true })
+  completedDate?: Date;
+
+  @Column({ name: 'estimated_cost', type: 'numeric', precision: 14, scale: 2, nullable: true })
+  estimatedCost?: number;
+
+  @Column({ name: 'actual_cost', type: 'numeric', precision: 14, scale: 2, nullable: true })
+  actualCost?: number;
+
+  @Column({ name: 'status', type: 'varchar', default: MaintenanceStatus.SCHEDULED })
+  status!: MaintenanceStatus;
+
+  @Column({ name: 'odometer_reading', type: 'numeric', nullable: true })
+  odometerReading?: number;
+
+  @Column({ name: 'service_provider', nullable: true })
+  serviceProvider?: string;
+
+  @Column({ name: 'notes', type: 'text', nullable: true })
+  notes?: string;
+
+  @Column({ name: 'next_due_km', type: 'numeric', nullable: true })
+  nextDueKm?: number;
+
+  @Column({ name: 'next_due_date', type: 'timestamptz', nullable: true })
+  nextDueDate?: Date;
+}