feat: driver documents (sovereignty storage adapter) + load-test script

- documents: upload (multipart) + review (admin/CS) + auto-approve driver when all docs approved
- StorageService: per-tenant local volume now, in-country storage swap via STORAGE_BASE_URL
- doc.number encrypted (AES-256-GCM); migration InitDocuments; tripz-storage volume
- scripts/loadtest.mjs: concurrent full trip-cycle benchmark (throughput + latency percentiles)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

backend/src/modules/documents/entities/driver-document.entity.ts

@@ -0,0 +1,61 @@
+import {
+  Column,
+  CreateDateColumn,
+  Entity,
+  Index,
+  PrimaryGeneratedColumn,
+  UpdateDateColumn,
+} from 'typeorm';
+import { EncryptedTransformer } from '../../../common/crypto/crypto.util';
+
+export type DocType =
+  | 'license'
+  | 'national_id'
+  | 'vehicle_registration'
+  | 'insurance'
+  | 'selfie'
+  | 'vehicle_photo';
+export type DocStatus = 'pending' | 'approved' | 'rejected';
+
+/** وثيقة سائق (صورة + بيانات). الجدول: tripz_driver_documents. */
+@Entity('driver_documents')
+@Index(['tenant_id', 'driver_id'])
+@Index(['tenant_id', 'status'])
+export class DriverDocument {
+  @PrimaryGeneratedColumn('uuid')
+  id: string;
+
+  @Column({ type: 'uuid' })
+  tenant_id: string;
+
+  @Column({ type: 'uuid' })
+  driver_id: string;
+
+  @Column()
+  type: DocType;
+
+  @Column()
+  file_key: string; // مفتاح التخزين (سيرفر التوطين لاحقاً)
+
+  // رقم الرخصة/الهوية — مشفّر at-rest (AES-256-GCM)
+  @Column({ type: 'varchar', nullable: true, transformer: EncryptedTransformer })
+  number: string | null;
+
+  @Column({ type: 'date', nullable: true })
+  expiry_date: string | null;
+
+  @Column({ type: 'varchar', default: 'pending' })
+  status: DocStatus;
+
+  @Column({ type: 'varchar', nullable: true })
+  review_note: string | null;
+
+  @Column({ type: 'uuid', nullable: true })
+  reviewed_by: string | null;
+
+  @CreateDateColumn()
+  created_at: Date;
+
+  @UpdateDateColumn()
+  updated_at: Date;
+}