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_shared_schema_bridge.py

@@ -0,0 +1,32 @@
+# -*- coding: utf-8 -*-
+"""Regression coverage for the shared schema bridge."""
+
+from backend.data import schema as legacy_schema
+from shared import schema as shared_schema
+
+
+def test_backend_data_schema_reexports_shared_contracts():
+    assert legacy_schema.Price is shared_schema.Price
+    assert legacy_schema.PriceResponse is shared_schema.PriceResponse
+    assert legacy_schema.FinancialMetrics is shared_schema.FinancialMetrics
+    assert legacy_schema.FinancialMetricsResponse is (
+        shared_schema.FinancialMetricsResponse
+    )
+    assert legacy_schema.LineItem is shared_schema.LineItem
+    assert legacy_schema.LineItemResponse is shared_schema.LineItemResponse
+    assert legacy_schema.InsiderTrade is shared_schema.InsiderTrade
+    assert legacy_schema.InsiderTradeResponse is (
+        shared_schema.InsiderTradeResponse
+    )
+    assert legacy_schema.CompanyNews is shared_schema.CompanyNews
+    assert legacy_schema.CompanyNewsResponse is shared_schema.CompanyNewsResponse
+    assert legacy_schema.CompanyFacts is shared_schema.CompanyFacts
+    assert legacy_schema.CompanyFactsResponse is (
+        shared_schema.CompanyFactsResponse
+    )
+    assert legacy_schema.Position is shared_schema.Position
+    assert legacy_schema.Portfolio is shared_schema.Portfolio
+    assert legacy_schema.AnalystSignal is shared_schema.AnalystSignal
+    assert legacy_schema.TickerAnalysis is shared_schema.TickerAnalysis
+    assert legacy_schema.AgentStateData is shared_schema.AgentStateData
+    assert legacy_schema.AgentStateMetadata is shared_schema.AgentStateMetadata