style(auth): 优化auth模块代码规范

范围: src/business/auth/
- register.service.ts: 清理未使用的导入TokenPair，增强userId非空验证
- register.service.spec.ts: 清理未使用的变量apiKeySecurityService

src/business/auth/register.service.spec.ts

@@ -7,12 +7,13 @@
  * - 测试Zulip账号集成
  * 
  * 最近修改：
+ * - 2026-01-15: 代码规范优化 - 清理未使用的变量apiKeySecurityService (修改者: moyin)
  * - 2026-01-12: 代码分离 - 从login.service.spec.ts中分离注册相关测试
  * 
  * @author moyin
- * @version 1.0.0
+ * @version 1.0.1
  * @since 2026-01-12
- * @lastModified 2026-01-12
+ * @lastModified 2026-01-15
  */
 
 import { Test, TestingModule } from '@nestjs/testing';
@@ -25,7 +26,6 @@ describe('RegisterService', () => {
   let service: RegisterService;
   let loginCoreService: jest.Mocked<LoginCoreService>;
   let zulipAccountService: jest.Mocked<ZulipAccountService>;
-  let apiKeySecurityService: jest.Mocked<ApiKeySecurityService>;
 
   const mockUser = {
     id: BigInt(1),
@@ -96,7 +96,6 @@ describe('RegisterService', () => {
     service = module.get<RegisterService>(RegisterService);
     loginCoreService = module.get(LoginCoreService);
     zulipAccountService = module.get(ZulipAccountService);
-    apiKeySecurityService = module.get(ApiKeySecurityService);
 
     // 设置默认的mock返回值
     const mockTokenPair = {

src/business/auth/register.service.ts

@@ -14,16 +14,17 @@
  * - 处理注册相关的邮箱验证和Zulip集成
  * 
  * 最近修改：
+ * - 2026-01-15: 代码规范优化 - 清理未使用的导入TokenPair，增强userId非空验证 (修改者: moyin)
  * - 2026-01-12: 代码分离 - 从login.service.ts中分离注册相关业务逻辑
  * 
  * @author moyin
- * @version 1.0.0
+ * @version 1.0.1
  * @since 2026-01-12
- * @lastModified 2026-01-12
+ * @lastModified 2026-01-15
  */
 
 import { Injectable, Logger, Inject } from '@nestjs/common';
-import { LoginCoreService, RegisterRequest, TokenPair } from '../../core/login_core/login_core.service';
+import { LoginCoreService, RegisterRequest } from '../../core/login_core/login_core.service';
 import { Users } from '../../core/db/users/users.entity';
 import { ZulipAccountService } from '../../core/zulip_core/services/zulip_account.service';
 import { ApiKeySecurityService } from '../../core/zulip_core/services/api_key_security.service';
@@ -487,6 +488,11 @@ export class RegisterService {
         throw new Error(createResult.error || 'Zulip账号创建/绑定失败');
       }
 
+      // 验证必须获取到 userId（数据库字段 NOT NULL）
+      if (createResult.userId === undefined || createResult.userId === null) {
+        throw new Error('Zulip账号创建成功但未能获取用户ID，无法建立关联');
+      }
+
       // 3. 处理API Key
       let finalApiKey = createResult.apiKey;
       
@@ -520,7 +526,7 @@ export class RegisterService {
       // 5. 在数据库中创建关联记录
       await this.zulipAccountsService.create({
         gameUserId: gameUser.id.toString(),
-        zulipUserId: createResult.userId!,
+        zulipUserId: createResult.userId,  // 已在上面验证不为 undefined
         zulipEmail: createResult.email!,
         zulipFullName: gameUser.nickname,
         zulipApiKeyEncrypted: finalApiKey ? 'stored_in_redis' : '',
@@ -531,7 +537,7 @@ export class RegisterService {
       if (finalApiKey) {
         await this.zulipAccountService.linkGameAccount(
           gameUser.id.toString(),
-          createResult.userId!,
+          createResult.userId,  // 已在上面验证不为 undefined
           createResult.email!,
           finalApiKey
         );