fix(HEL-494): 网站市场客户端改为纯中枢 Facade，并迁移 iFinD 凭据到中枢

生产 gateway 不再读取 Tushare token 或实例化 TushareProvider/TushareClient；问财凭据经带鉴权的中枢接口加密入库，避免发版后 iFinD 未配置。

Co-authored-by: Cursor <cursoragent@cursor.com>
Co-authored-by: multica-agent <github@multica.ai>

backend/data/gateway.py

@@ -10,9 +10,8 @@ from backend.data.datahub import DatahubAwareTushareClient, DatahubBridge, Datah
 from backend.data.datahub.ifind_proxy import HubIfindProxy
 from backend.data.datahub.realtime_proxy import HubRealtimeProxy
 from backend.data.policy import DataSourcePolicy
-from backend.data.providers import IfindProvider, TushareProvider
+from backend.data.providers import IfindProvider
 from backend.data.quality import DataQualityGate, QualityEvidence, QualityReport
-from backend.data.providers.tushare_client import TushareClient
 from backend.features.market.charts import MarketChartClient
 
 
@@ -20,7 +19,6 @@ from backend.features.market.charts import MarketChartClient
 class DataGateway:
     policy: DataSourcePolicy
     quality: DataQualityGate
-    tushare_provider: TushareProvider
     ifind_provider: IfindProvider
     chart_data: MarketChartClient
     realtime_observer: HubRealtimeProxy
@@ -34,12 +32,10 @@ class DataGateway:
         self,
         dataset_id: str = "",
         usage: DataUsage = "calculation",
-    ) -> TushareClient:
+    ) -> DatahubAwareTushareClient:
         if dataset_id:
             self.policy.assert_allowed(dataset_id, "tushare", usage)
-        legacy = self.tushare_provider.client()
-        legacy.realtime_aggregator = None
-        return DatahubAwareTushareClient(legacy, self.datahub)
+        return DatahubAwareTushareClient(self.datahub)
 
     def dataset_status(self, trade_date: str) -> list[dict[str, Any]] | None:
         return self.datahub.dataset_status(trade_date)
@@ -102,9 +98,8 @@ def build_data_gateway(
     tushare_token_supplier: Callable[[], str] | None = None,
     datahub_settings: DatahubSettings | None = None,
 ) -> DataGateway:
-    token_supplier = tushare_token_supplier or (
-        lambda: str(credentials.get("tushare_token") or "")
-    )
+    # Website Tushare tokens are not used to assemble market clients.
+    del tushare_token_supplier
     policy = DataSourcePolicy.load()
     settings = datahub_settings or DatahubSettings.load(credentials=credentials)
     datahub_client = DatahubClient(settings)
@@ -113,7 +108,6 @@ def build_data_gateway(
     return DataGateway(
         policy=policy,
         quality=DataQualityGate.load(policy),
-        tushare_provider=TushareProvider(token_supplier),
         ifind_provider=IfindProvider(ifind),
         chart_data=MarketChartClient(datahub),
         realtime_observer=HubRealtimeProxy(datahub),