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/tests/test_trading_domain.py

@@ -0,0 +1,47 @@
+# -*- coding: utf-8 -*-
+"""Unit tests for the trading domain helpers."""
+
+from backend.domains import trading as trading_domain
+
+
+def test_trading_domain_payload_wrappers(monkeypatch):
+    monkeypatch.setattr(trading_domain, "get_prices", lambda ticker, start_date, end_date: [{"close": 1}])
+    monkeypatch.setattr(trading_domain, "get_financial_metrics", lambda ticker, end_date, period, limit: [{"ticker": ticker}])
+    monkeypatch.setattr(trading_domain, "get_company_news", lambda ticker, end_date, start_date=None, limit=1000: [{"ticker": ticker}])
+    monkeypatch.setattr(trading_domain, "get_insider_trades", lambda ticker, end_date, start_date=None, limit=1000: [{"ticker": ticker}])
+    monkeypatch.setattr(trading_domain, "get_market_cap", lambda ticker, end_date: 2.5e12)
+
+    assert trading_domain.get_prices_payload(ticker="AAPL", start_date="2026-03-01", end_date="2026-03-16") == {
+        "ticker": "AAPL",
+        "prices": [{"close": 1}],
+    }
+    assert trading_domain.get_financials_payload(ticker="AAPL", end_date="2026-03-16") == {
+        "financial_metrics": [{"ticker": "AAPL"}],
+    }
+    assert trading_domain.get_news_payload(ticker="AAPL", end_date="2026-03-16") == {
+        "news": [{"ticker": "AAPL"}],
+    }
+    assert trading_domain.get_insider_trades_payload(ticker="AAPL", end_date="2026-03-16") == {
+        "insider_trades": [{"ticker": "AAPL"}],
+    }
+    assert trading_domain.get_market_cap_payload(ticker="AAPL", end_date="2026-03-16") == {
+        "ticker": "AAPL",
+        "end_date": "2026-03-16",
+        "market_cap": 2.5e12,
+    }
+
+
+def test_get_market_status_payload_uses_market_service(monkeypatch):
+    class _FakeMarketService:
+        def __init__(self, tickers):
+            self.tickers = tickers
+
+        def get_market_status(self):
+            return {"status": "open", "status_text": "Open"}
+
+    monkeypatch.setattr(trading_domain, "MarketService", _FakeMarketService)
+
+    assert trading_domain.get_market_status_payload() == {
+        "status": "open",
+        "status_text": "Open",
+    }