feat(promo): generate WeChat mini-program codes on create

Use getwxacodeunlimit with activity id as scene, upload PNG to OSS qrcode/, and show in HQ admin.

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

apps/admin-web/src/pages/promo/PromoCodeDetailPage.tsx

@@ -74,25 +74,28 @@ export default function PromoCodeDetailPage() {
     <>
       <Row gutter={[16, 16]}>
         <Col xs={24} lg={8}>
-          <Card title="推广二维码" size="small">
+          <Card title="小程序码" size="small">
             {detail.qrcodeUrl ? (
               <div style={{ textAlign: 'center' }}>
                 <img
                   src={detail.qrcodeUrl}
-                  alt="推广二维码"
+                  alt="推广小程序码"
                   style={{ width: 200, height: 200, marginBottom: 12 }}
                 />
+                <Typography.Paragraph type="secondary" style={{ marginBottom: 12, fontSize: 12 }}>
+                  微信扫码进入小程序（scene=活动 ID {detail.id}）
+                </Typography.Paragraph>
                 <Space direction="vertical" style={{ width: '100%' }}>
                   <Button
                     block
-                    onClick={() => void downloadQrcode(detail.qrcodeUrl!, `${detail.code}-qrcode.png`)}
+                    onClick={() => void downloadQrcode(detail.qrcodeUrl!, `${detail.code}-wxacode.png`)}
                   >
-                    下载二维码
+                    下载小程序码
                   </Button>
                 </Space>
               </div>
             ) : (
-              <Typography.Text type="secondary">暂无二维码</Typography.Text>
+              <Typography.Text type="secondary">暂无小程序码</Typography.Text>
             )}
           </Card>
         </Col>
@@ -144,13 +147,18 @@ export default function PromoCodeDetailPage() {
               <Descriptions.Item label="状态">
                 {PROMO_CODE_STATUS_LABELS[detail.status] || detail.status}
               </Descriptions.Item>
+              <Descriptions.Item label="活动 ID" span={2}>
+                <Typography.Text copyable={{ text: String(detail.id) }}>
+                  {detail.id}（小程序码 scene）
+                </Typography.Text>
+              </Descriptions.Item>
               <Descriptions.Item label="二维码 ID" span={2}>
                 <Typography.Text copyable={{ text: detail.qrcodeId }}>{detail.qrcodeId}</Typography.Text>
               </Descriptions.Item>
-              <Descriptions.Item label="落地链接" span={2}>
+              <Descriptions.Item label="H5 落地链接" span={2}>
                 <Typography.Text copyable={{ text: detail.landingUrl }}>{detail.landingUrl}</Typography.Text>
               </Descriptions.Item>
-              <Descriptions.Item label="OSS 地址" span={2}>
+              <Descriptions.Item label="小程序码 OSS" span={2}>
                 {detail.qrcodeUrl ? (
                   <Typography.Text copyable={{ text: detail.qrcodeUrl }} ellipsis>
                     {detail.qrcodeUrl}