refactor：重构Zulip模块按业务功能模块化架构

- 将技术实现服务从business层迁移到core层
- 创建src/core/zulip/核心服务模块，包含API客户端、连接池等技术服务
- 保留src/business/zulip/业务逻辑，专注游戏相关的业务规则
- 通过依赖注入实现业务层与核心层的解耦
- 更新模块导入关系，确保架构分层清晰

重构后的架构符合单一职责原则，提高了代码的可维护性和可测试性

src/core/zulip/zulip-core.module.ts

@@ -0,0 +1,68 @@
+/**
+ * Zulip核心服务模块
+ * 
+ * 功能描述：
+ * - 提供Zulip技术实现相关的核心服务
+ * - 封装第三方API调用和技术细节
+ * - 为业务层提供抽象接口
+ * 
+ * @author angjustinl
+ * @version 1.0.0
+ * @since 2025-12-31
+ */
+
+import { Module } from '@nestjs/common';
+import { ZulipClientService } from './services/zulip_client.service';
+import { ZulipClientPoolService } from './services/zulip_client_pool.service';
+import { ConfigManagerService } from './services/config_manager.service';
+import { ApiKeySecurityService } from './services/api_key_security.service';
+import { ErrorHandlerService } from './services/error_handler.service';
+import { MonitoringService } from './services/monitoring.service';
+import { StreamInitializerService } from './services/stream_initializer.service';
+import { RedisModule } from '../redis/redis.module';
+
+@Module({
+  imports: [
+    // Redis模块 - ApiKeySecurityService需要REDIS_SERVICE
+    RedisModule,
+  ],
+  providers: [
+    // 核心客户端服务
+    {
+      provide: 'ZULIP_CLIENT_SERVICE',
+      useClass: ZulipClientService,
+    },
+    {
+      provide: 'ZULIP_CLIENT_POOL_SERVICE',
+      useClass: ZulipClientPoolService,
+    },
+    {
+      provide: 'ZULIP_CONFIG_SERVICE',
+      useClass: ConfigManagerService,
+    },
+    
+    // 辅助服务
+    ApiKeySecurityService,
+    ErrorHandlerService,
+    MonitoringService,
+    StreamInitializerService,
+    
+    // 直接提供类（用于内部依赖）
+    ZulipClientService,
+    ZulipClientPoolService,
+    ConfigManagerService,
+  ],
+  exports: [
+    // 导出接口标识符供业务层使用
+    'ZULIP_CLIENT_SERVICE',
+    'ZULIP_CLIENT_POOL_SERVICE',
+    'ZULIP_CONFIG_SERVICE',
+    
+    // 导出辅助服务
+    ApiKeySecurityService,
+    ErrorHandlerService,
+    MonitoringService,
+    StreamInitializerService,
+  ],
+})
+export class ZulipCoreModule {}