feat(HEL-402): 接通网站首批只读 datahub 并建立双路对比

默认全部读取/影子开关关闭，网站继续走旧 Tushare 链路；开启单项时只替换该类原料并在失败时回旧，问天保持旧路径。

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

config/architecture-inventory.json

@@ -204,6 +204,11 @@
       "path": "backend/data/providers/tushare_client.py",
       "runtime_role": "stable client facade for primary deterministic market data"
     },
+    {
+      "provider": "datahub",
+      "path": "backend/data/datahub/client.py",
+      "runtime_role": "optional official EOD read path behind per-dataset flags"
+    },
     {
       "provider": "ifind",
       "path": "backend/data/providers/ifind_client.py",
@@ -278,6 +283,18 @@
       "owner": "backend/data/providers/tushare.py",
       "compatibility_fallback": "backend/features/market/service.py"
     },
+    {
+      "client": "DatahubClient",
+      "owner": "backend/data/gateway.py"
+    },
+    {
+      "client": "DatahubBridge",
+      "owner": "backend/data/gateway.py"
+    },
+    {
+      "client": "DatahubAwareTushareClient",
+      "owner": "backend/data/gateway.py"
+    },
     {
       "client": "IfindHttpClient",
       "owner": "backend/data/gateway.py"