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>

frontend/m/js/pages.js

@@ -5219,6 +5219,15 @@
     return '<span class="m-sys-dot' + (ok ? " m-sys-dot--ok" : "") + '"></span>';
   }
 
+  function datahubStatusText(hub) {
+    const enabled = number(hub.enabled_reads);
+    const total = number(hub.total_reads) || enabled;
+    const fallbacks = hub.fallback_labels || [];
+    if (fallbacks.length) return " 备用 " + fallbacks.join("、");
+    if (hub.configured) return " 主线路 " + enabled + "/" + total;
+    return " 未配置";
+  }
+
   function renderSystemAdmin(key) {
     if (key === "system/members") {
       renderSystemMembers();
@@ -5237,6 +5246,7 @@
       '<div class="m-sys-status-item"><span>iFinD</span><span>' + statusDot(ifind.configured) + (ifind.configured ? " 已配置" : " 未配置") + "</span></div>" +
       '<div class="m-sys-status-item"><span>行情快照</span><strong>' + number(data.snapshot_dates) + " 个交易日</strong></div>" +
       '<div class="m-sys-status-item"><span>后台刷新</span><span>' + statusDot(data.background_refresh_enabled) + (data.background_refresh_enabled ? " 已启用" : " 已暂停") + "</span></div>" +
+      '<div class="m-sys-status-item"><span>数据中枢</span><span>' + statusDot(Boolean((data.datahub || {}).configured) && !((data.datahub || {}).fallback_count)) + datahubStatusText(data.datahub || {}) + "</span></div>" +
       "</div></div>" +
       '<div class="m-card m-sys-section"><strong>数据源密钥</strong>' +
       formFieldHtml("Tushare Token", '<input id="m-sys-token" type="password" autocomplete="off" minlength="20" placeholder="留空则保留现有 Token">', false) +