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>

frontend/src/components/explain/ExplainNewsSection.jsx

@@ -1,6 +1,12 @@
 import React from 'react';
 import { formatDateTime } from '../../utils/formatters';
 
+function renderFreshness(freshness) {
+  if (!freshness || typeof freshness !== 'object') return null;
+  const lastFetch = freshness.last_news_fetch || '-';
+  return `新闻更新到 ${lastFetch}${freshness.refreshed ? ' · 本次已刷新' : ''}`;
+}
+
 function categoryLabel(value) {
   const normalized = String(value || '').trim().toLowerCase();
   const labels = {
@@ -47,6 +53,7 @@ export default function ExplainNewsSection({
   newsSnapshot,
   visibleNewsByCategory,
   visibleNews,
+  selectedNewsFreshness,
   activeNewsCategory,
   onSelectNewsCategory,
   activeNewsSentiment,
@@ -64,6 +71,11 @@ export default function ExplainNewsSection({
           <div style={{ fontSize: 11, color: '#666666' }}>
             {newsSnapshot?.source ? `最近 ${visibleNewsByCategory.length} 条 · ${newsSnapshot.source}` : `最近 ${visibleNewsByCategory.length} 条真实新闻`}
           </div>
+          {renderFreshness(selectedNewsFreshness) ? (
+            <div style={{ fontSize: 11, color: '#666666' }}>
+              {renderFreshness(selectedNewsFreshness)}
+            </div>
+          ) : null}
           <button
             onClick={onToggle}
             style={{