fix(HEL-494): 切断网站生产装配外源直连，iFinD 与实时观察改走中枢

生产 gateway 不再实例化 iFinD、东财图和免费实时聚合器；问财与竞价快照作为中枢内部数据源。全站阻断外源测试覆盖日K、报价、图表、问财和竞价快照。

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

backend/data/providers/ifind.py

@@ -1,11 +1,13 @@
 from __future__ import annotations
 
-from backend.data.providers.ifind_client import IfindHttpClient
+from typing import Any
 
 
 class IfindProvider:
-    def __init__(self, client: IfindHttpClient) -> None:
+    def __init__(self, client: Any) -> None:
         self.client = client
 
     def set_credentials(self, refresh_token: str, access_token: str = "") -> None:
-        self.client.set_credentials(refresh_token, access_token)
+        setter = getattr(self.client, "set_credentials", None)
+        if callable(setter):
+            setter(refresh_token, access_token)