fix: 修复前端访问payParams时的空值检查，避免cannot read property appId错误

my-uniapp-vue3/src/pages/payment-confirm/index.vue

@@ -327,21 +327,28 @@ async function handleWechatJsapiPay() {
     uni.hideLoading();
 
     // 使用 WeixinJSBridge.invoke 调起支付
+    const currentResult = result; // 保存引用，避免闭包问题
     const onBridgeReady = () => {
+      if (!currentResult || !currentResult.payParams) {
+        console.error('[WeChat Pay] payParams 不存在:', currentResult);
+        uni.showToast({ title: '支付参数异常，请重试', icon: 'none' });
+        paying.value = false;
+        return;
+      }
       (window as any).WeixinJSBridge.invoke(
         'getBrandWXPayRequest',
         {
-          "appId": result.payParams.appId,
-          "timeStamp": result.payParams.timeStamp,
-          "nonceStr": result.payParams.nonceStr,
-          "package": result.payParams.package,
-          "signType": result.payParams.signType || "RSA",
-          "paySign": result.payParams.paySign,
+          "appId": currentResult.payParams.appId,
+          "timeStamp": currentResult.payParams.timeStamp,
+          "nonceStr": currentResult.payParams.nonceStr,
+          "package": currentResult.payParams.package,
+          "signType": currentResult.payParams.signType || "RSA",
+          "paySign": currentResult.payParams.paySign,
         },
         async (res: any) => {
           console.log('[WeChat Pay] WeixinJSBridge 回调:', JSON.stringify(res));
           // 官方要求：必须调用查询订单API确认最终状态
-          const orderStatus = await checkWechatOrderStatus(result.orderNo);
+          const orderStatus = await checkWechatOrderStatus(currentResult.orderNo);
           paying.value = false;
 
           if (res.err_msg === "get_brand_wcpay_request:ok") {
@@ -372,7 +379,7 @@ async function handleWechatJsapiPay() {
               confirmText: '扫码支付',
               cancelText: '取消',
               success: (modalRes: any) => {
-                if (modalRes.confirm && result.orderNo) {
+                if (modalRes.confirm && currentResult.orderNo) {
                   inWechat.value = false;
                   handlePay();
                 }