fix(issuer/user): fix TypeORM databaseName error in coupon join + wallet frozen column name

- Replace leftJoinAndMapOne(Issuer entity) with two-step query to avoid TypeORM
  metadata lookup error ('Cannot read databaseName of undefined')
- Extract unique issuer IDs from coupon results, then batch-fetch issuers and attach
- Fix wallet entity: map frozenBalance to 'frozen' column (not 'frozen_balance')

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/services/issuer-service/src/infrastructure/persistence/coupon.repository.ts

@@ -1,6 +1,6 @@
 import { Injectable, NotFoundException, BadRequestException } from '@nestjs/common';
 import { InjectRepository } from '@nestjs/typeorm';
-import { Repository, DataSource } from 'typeorm';
+import { Repository, DataSource, In } from 'typeorm';
 import { Coupon, CouponStatus } from '../../domain/entities/coupon.entity';
 import { Issuer } from '../../domain/entities/issuer.entity';
 import {
@@ -61,8 +61,6 @@ export class CouponRepository implements ICouponRepository {
     const { category, status, search, issuerId, page, limit } = filters;
     const qb = this.repo.createQueryBuilder('c');
 
-    qb.leftJoinAndMapOne('c.issuer', Issuer, 'i', 'i.id = c.issuer_id');
-
     if (status) qb.andWhere('c.status = :status', { status });
     if (issuerId) qb.andWhere('c.issuer_id = :issuerId', { issuerId });
     if (category) qb.andWhere('c.category = :category', { category });
@@ -76,23 +74,33 @@ export class CouponRepository implements ICouponRepository {
       .skip((page - 1) * limit)
       .take(limit);
 
-    return qb.getManyAndCount();
+    const [coupons, total] = await qb.getManyAndCount();
+    await this._attachIssuers(coupons);
+    return [coupons, total];
   }
 
   async findByOwnerWithIssuerJoin(userId: string, filters: CouponListFilters): Promise<[Coupon[], number]> {
     const { status, page, limit } = filters;
     const qb = this.repo.createQueryBuilder('c');
 
-    qb.leftJoinAndMapOne('c.issuer', Issuer, 'i', 'i.id = c.issuer_id');
     qb.andWhere('c.owner_user_id = :userId', { userId });
-
     if (status) qb.andWhere('c.status = :status', { status });
 
     qb.orderBy('c.created_at', 'DESC')
       .skip((page - 1) * limit)
       .take(limit);
 
-    return qb.getManyAndCount();
+    const [coupons, total] = await qb.getManyAndCount();
+    await this._attachIssuers(coupons);
+    return [coupons, total];
+  }
+
+  private async _attachIssuers(coupons: Coupon[]): Promise<void> {
+    if (coupons.length === 0) return;
+    const issuerIds = [...new Set(coupons.map((c) => c.issuerId))];
+    const issuers = await this.dataSource.getRepository(Issuer).findBy({ id: In(issuerIds) });
+    const issuerMap = new Map(issuers.map((i) => [i.id, i]));
+    coupons.forEach((c) => { c.issuer = issuerMap.get(c.issuerId); });
   }
 
   async getOwnerSummary(userId: string): Promise<OwnerSummary> {

backend/services/user-service/src/domain/entities/wallet.entity.ts

@@ -9,7 +9,7 @@ export class Wallet {
   @PrimaryGeneratedColumn('uuid') id: string;
   @Column({ name: 'user_id', type: 'uuid', unique: true }) userId: string;
   @Column({ type: 'numeric', precision: 20, scale: 8, default: '0' }) balance: string;
-  @Column({ name: 'frozen_balance', type: 'numeric', precision: 20, scale: 8, default: '0' }) frozenBalance: string;
+  @Column({ name: 'frozen', type: 'numeric', precision: 20, scale: 8, default: '0' }) frozenBalance: string;
   @Column({ type: 'varchar', length: 10, default: 'USD' }) currency: string;
   @Column({ type: 'varchar', length: 20, default: 'active' }) status: string;
   @CreateDateColumn({ name: 'created_at', type: 'timestamptz' }) createdAt: Date;