fix: 回退HTTP+签名URL，七牛默认CDN域名不支持HTTPS证书

par-core/src/main/java/com/par/core/storage/QiniuStorageService.java

@@ -87,8 +87,8 @@ public class QiniuStorageService implements StorageService {
             log.warn("Qiniu stat 失败 {}: {}", path, e.response != null ? e.response.error : e.getMessage());
         }
 
-        // 用 HTTPS 签名 URL 拉取
-        String baseUrl = "https://" + downloadDomain + "/" + path;
+        // HTTP 签名 URL 拉取（七牛默认CDN域名不支持HTTPS）
+        String baseUrl = "http://" + downloadDomain + "/" + path;
         String signedUrl = auth.privateDownloadUrl(baseUrl, 3600);
         try {
             var req = HttpRequest.newBuilder().uri(URI.create(signedUrl))