fix: null guard toFixed in ThemeStockRow to prevent crash when API returns null

src/routes/theme.$code.tsx

@@ -351,11 +351,11 @@ function NewsList({
 function ThemeStockRow({ stock }: { stock: ThemeStock }) {
   const [showReason, setShowReason] = useState(true); // 入选理由默认展开
   const board = getStockBoard(stock.securityCode);
-  const isPos = stock.f3 >= 0;
+  const isPos = (stock.f3 ?? 0) >= 0;
   const reasons = stock.keywordList ?? [];
 
   // 换手率：接口返回放大 100 倍的值（如 3733 = 37.33%）
-  const turnoverRate = stock.f8 > 100 ? stock.f8 / 100 : stock.f8;
+  const turnoverRate = stock.f8 != null ? (stock.f8 > 100 ? stock.f8 / 100 : stock.f8) : null;
 
   return (
     <Link to="/stock/$code" params={{ code: stock.securityCode }} className="block">
@@ -381,13 +381,13 @@ function ThemeStockRow({ stock }: { stock: ThemeStock }) {
             <div className="flex items-center gap-3 shrink-0">
               <div className="text-right">
                 <p className="text-[10px] text-muted-foreground">现价</p>
-                <p className="text-sm font-semibold tabular-nums">{stock.f2.toFixed(2)}</p>
+                <p className="text-sm font-semibold tabular-nums">{stock.f2 != null ? stock.f2.toFixed(2) : "--"}</p>
               </div>
               <div className="text-right min-w-[56px]">
                 <p className="text-[10px] text-muted-foreground">涨跌</p>
                 <p className={`text-sm font-bold tabular-nums ${isPos ? "text-red-500" : "text-green-500"}`}>
                   {isPos ? "+" : ""}
-                  {stock.f3.toFixed(2)}%
+                  {stock.f3 != null ? stock.f3.toFixed(2) : "--"}%
                 </p>
               </div>
             </div>
@@ -398,7 +398,7 @@ function ThemeStockRow({ stock }: { stock: ThemeStock }) {
             {stock.f100 && (
               <span className="truncate bg-muted rounded px-1.5 py-0.5 text-[10px]">{stock.f100}</span>
             )}
-            <span className="shrink-0 tabular-nums">换手 {turnoverRate.toFixed(2)}%</span>
+            <span className="shrink-0 tabular-nums">换手 {turnoverRate != null ? turnoverRate.toFixed(2) : "--"}%</span>
             <span className="shrink-0 tabular-nums">主力 {formatMoney(stock.f62)}</span>
             <span className="shrink-0 tabular-nums ml-auto">成交 {formatMoney(stock.f6)}</span>
           </div>