fix: mobile scroll - remove nested overflow on mobile, disable sticky thead on mobile, 2s interval

frontend/app/trades/page.tsx

@@ -80,7 +80,7 @@ function LiveTrades({ symbol }: { symbol: Symbol }) {
       } catch {}
     };
     fetch();
-    const iv = setInterval(fetch, 1000);
+    const iv = setInterval(fetch, 2000); // 移动端友好：2秒刷新降低重排
     return () => { running = false; clearInterval(iv); };
   }, [symbol]);
 
@@ -99,13 +99,14 @@ function LiveTrades({ symbol }: { symbol: Symbol }) {
           <span className="text-red-500 font-medium">▼ 红</span>=主动卖（空方发动）
         </p>
       </div>
-      {/* 固定高度容器，内部自己滚动，不影响页面 */}
-      <div className="overflow-y-auto" style={{ height: 420 }}>
+      {/* 桌面端固定高度内滚，手机端展开不嵌套滚动 */}
+      <div className="lg:overflow-y-auto lg:h-[420px]">
         {loading ? (
           <div className="flex items-center justify-center h-24 text-slate-400 text-sm">加载中...</div>
         ) : (
           <table className="w-full text-xs">
-            <thead className="sticky top-0 bg-white z-10 shadow-sm">
+            {/* 手机端关闭sticky，避免触摸焦点被内层抢走 */}
+            <thead className="lg:sticky lg:top-0 bg-white z-10 shadow-sm">
               <tr className="bg-slate-50 border-b border-slate-100">
                 <th className="text-left px-3 py-2 text-slate-500 font-medium">价格</th>
                 <th className="text-right px-3 py-2 text-slate-500 font-medium">数量</th>