feat(HEL-490): 剩余行情改由数据中枢主线路提供

正式页面以 8766 为主线路，旧接口只作故障备用；compose 钉死全部 DATAHUB_READ_*，避免现网残留 0 造成假完成。

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

tests/test_http_dispatch.py

@@ -138,7 +138,7 @@ class HttpDispatchContractTests(unittest.TestCase):
             self.assertTrue(claimed.isdisjoint(methods))
             claimed.update(methods)
             self.assertLessEqual(len(path.read_text(encoding="utf-8").splitlines()), line_limit)
-        self.assertEqual(len(claimed), 27)
+        self.assertEqual(len(claimed), 28)
 
 
 if __name__ == "__main__":