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>

config/README.md

@@ -12,9 +12,12 @@ These registries describe the approved product surface of the standalone applica
   providers, model entry points, CSS layers, and remaining code hotspots.
 - `data-fields.config.json`: canonical data products, provider eligibility, intended use, and
   known blocked datasets.
-- `datahub.config.json`: optional read-only client for `xiaobai-datahub`. Each dataset has its
-  own `read` / `shadow` flag, all default off. Environment variables `DATAHUB_READ_*` and
-  `DATAHUB_SHADOW_*` can override a single dataset without a master switch.
+- `datahub.config.json`: official read-only client for `xiaobai-datahub`. Each dataset has its
+  own `read` / `shadow` flag; official reads default on. `compose.yaml` pins every
+  `DATAHUB_READ_*` to `"1"` so a leftover `.env` `=0` cannot silently keep official
+  pages on the old APIs. Environment variables can still override a single
+  `DATAHUB_SHADOW_*` without a master switch. The old website APIs stay as
+  emergency fallback only.
 - `data-quality.config.json`: freshness, coverage, units, adjustment, point-in-time, and
   fail-closed rules for every canonical data product.
 - `jobs.config.json`: background schedules, dependencies, lock keys, retry policy, timeouts,