feat: 微服务架构拆分和前后端优化

后端:
- 拆分出 agent_service, runtime_service, trading_service, news_service
- Gateway 模块化拆分 (gateway_*.py)
- 添加 domains/ 领域层
- 新增 control_client, runtime_client
- 更新 start-dev.sh 支持 split 服务模式

前端:
- 完善 API 服务层 (newsApi, tradingApi)
- 更新 vite.config.js
- Explain 组件优化

测试:
- 添加多个服务 app 测试

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

backend/apps/__init__.py

@@ -0,0 +1,27 @@
+# -*- coding: utf-8 -*-
+"""Application surfaces for progressive service extraction."""
+
+from .agent_service import app as agent_app
+from .agent_service import create_app as create_agent_app
+from .news_service import app as news_app
+from .news_service import create_app as create_news_app
+from .runtime_service import app as runtime_app
+from .runtime_service import create_app as create_runtime_app
+from .trading_service import app as trading_app
+from .trading_service import create_app as create_trading_app
+
+app = agent_app
+create_app = create_agent_app
+
+__all__ = [
+    "app",
+    "create_app",
+    "agent_app",
+    "create_agent_app",
+    "news_app",
+    "create_news_app",
+    "runtime_app",
+    "create_runtime_app",
+    "trading_app",
+    "create_trading_app",
+]