重构 API 为 8 领域 + 应用层架构

将后端模块拆分为 domains、applications、shared 三层，结算计算器移入 domain 纯函数目录，API 路径与测试保持不变。

Co-authored-by: Cursor <cursoragent@cursor.com>

apps/api/src/domains/identity/users.service.ts

@@ -0,0 +1,43 @@
+import { Injectable } from '@nestjs/common';
+import { PrismaService } from '../../shared/prisma/prisma.service';
+
+@Injectable()
+export class UsersService {
+  constructor(private prisma: PrismaService) {}
+
+  async findById(id: bigint) {
+    return this.prisma.user.findUnique({
+      where: { id },
+      include: { wallet: true, agentProfile: true, preferences: true },
+    });
+  }
+
+  async updateLocale(userId: bigint, locale: string) {
+    await this.prisma.user.update({
+      where: { id: userId },
+      data: { locale },
+    });
+    await this.prisma.userPreference.upsert({
+      where: { userId },
+      create: { userId, locale },
+      update: { locale },
+    });
+    return { locale };
+  }
+
+  async listPlayers(page = 1, pageSize = 20, parentId?: bigint) {
+    const where = { userType: 'PLAYER', ...(parentId ? { parentId } : {}) };
+    const skip = (page - 1) * pageSize;
+    const [items, total] = await Promise.all([
+      this.prisma.user.findMany({
+        where,
+        include: { wallet: true },
+        skip,
+        take: pageSize,
+        orderBy: { createdAt: 'desc' },
+      }),
+      this.prisma.user.count({ where }),
+    ]);
+    return { items, total, page, pageSize };
+  }
+}