Pack plan summary into multi-column layout for ultrawide screens.

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/src/pages/Plan.tsx

@@ -172,6 +172,7 @@ export default function PlanPage() {
       </div>
 
       <div className="card plan-summary" style={{ marginBottom: 12 }}>
+        <div className="plan-metrics">
         <div className="kv">
           <span>策略</span>
           <span>
@@ -236,13 +237,14 @@ export default function PlanPage() {
           <span className={`mono ${pnlClass(pos?.option_upl)}`}>{fmt(pos?.option_upl)}</span>
         </div>
         {plan?.last_error ? (
-          <div className="kv">
+          <div className="kv kv-span">
             <span>最近错误</span>
             <span className="err" style={{ margin: 0 }}>
               {plan.last_error}
             </span>
           </div>
         ) : null}
+        </div>
 
         <div className="pos-embed-grid">
           {open ? (