refactor(tables): share parent column grid in expandable child rows

- llmodels/model-routes/cluster child rows use ExpandedRowGrid + Cell
  (auto-flow spans, no parent-key/grid-line math)
- define --seal-table-row-min-height token in global.less
- routes created_at column: span -> fixed width 180

src/pages/cluster-management/clusters.tsx

@@ -358,6 +358,9 @@ const Clusters: React.FC = () => {
         dataList={list}
         provider={options.parent?.provider}
         clusterId={options.parent?.id}
+        gridTemplate={options.gridTemplate}
+        prefixWidth={options.prefixWidth}
+        columns={options.columns}
       />
     );
   };