feat(live): D-3 sanguo实盘分支(影子下单)+D期设计文档

D-3 模式A影子下单(spec §5):
- bridge_client.py: QMT bridge HTTP客户端(urllib, X-Bridge-Token, 失败不抛返回None)
- live_orchestrator: _shadow_trades_to_bridge 当日成交POST bridge(默认enabled=false)
- persistence: paper_shadow_orders幂等表+save_shadow_order/is_trade_shadowed
- config: data_platform.yaml加live段, token走env(BRIDGE_TOKEN)
- to_bridge_code symbol转换与guess_exchange一致(2位前缀)
安全: enabled=false默认关+token走env+幂等防重复+影子失败不阻断live_step

docs: phase3d-live-trading-design.md(D期完整设计)

sanguo_data/config.py

@@ -10,6 +10,7 @@ class DataConfig:
     validation: dict
     performance: dict
     risk_free_rate: float = 0.02   # 年化无风险利率（spec §195 资金占用成本归因）
+    live: dict | None = None   # 实盘集成（D期 spec §5），None/缺省=disabled
 
 def load_config(path: str) -> DataConfig:
     try:
@@ -29,6 +30,7 @@ def load_config(path: str) -> DataConfig:
         validation=raw.get("validation", {}),
         performance=raw.get("performance", {}),
         risk_free_rate=float(raw.get("risk_free_rate", 0.02)),
+        live=raw.get("live"),
     )