feat: 新增后台复制店铺商品目录接口

支持按用户ID复制商品类型、专区与商品，OSS图片独立拷贝，并提供覆盖/补充两种模式。

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

utils/oss_utils.py

@@ -184,6 +184,88 @@ def _upload_to_aliyun_oss(file_obj, file_path):
         return None
 
 
+def _url_to_oss_key(file_url):
+    """从完整 URL 或相对路径提取 OSS 对象 Key"""
+    if not file_url:
+        return None
+    file_url = str(file_url).strip()
+    if not file_url:
+        return None
+
+    oss_type = getattr(settings, 'OSS_TYPE', 'tencent')
+    if oss_type == 'tencent':
+        domain = getattr(settings, 'COS_DOMAIN', '')
+    elif oss_type == 'aliyun':
+        domain = getattr(settings, 'ALIYUN_OSS_DOMAIN', '')
+    else:
+        return None
+
+    if file_url.startswith('http'):
+        if domain and domain not in file_url:
+            return None
+        prefix = f"{domain.rstrip('/')}/"
+        if file_url.startswith(prefix):
+            return file_url[len(prefix):]
+        return file_url.split('://', 1)[-1].split('/', 1)[-1]
+
+    return file_url.lstrip('/')
+
+
+def copy_in_oss(src_key_or_url, dest_key):
+    """
+    在 OSS 内复制对象（服务端复制，不经过本地）
+    src_key_or_url: 源对象 Key 或完整 URL
+    dest_key: 目标对象 Key（相对路径）
+    返回: 成功 True，失败 False
+    """
+    try:
+        src_key = _url_to_oss_key(src_key_or_url)
+        if not src_key or not dest_key:
+            return False
+
+        dest_key = dest_key.lstrip('/')
+        oss_type = getattr(settings, 'OSS_TYPE', 'tencent')
+
+        if oss_type == 'tencent':
+            return _copy_in_tencent_cos(src_key, dest_key)
+        elif oss_type == 'aliyun':
+            return _copy_in_aliyun_oss(src_key, dest_key)
+        return False
+    except Exception as e:
+        print(f"OSS复制失败: {e}")
+        return False
+
+
+def _copy_in_tencent_cos(src_key, dest_key):
+    client = get_oss_client()
+    bucket = getattr(settings, 'COS_BUCKET', '')
+    region = getattr(settings, 'COS_REGION', 'ap-shanghai')
+    try:
+        client.copy_object(
+            Bucket=bucket,
+            Key=dest_key,
+            CopySource={
+                'Bucket': bucket,
+                'Region': region,
+                'Key': src_key,
+            },
+        )
+        return True
+    except Exception as e:
+        print(f"腾讯云COS复制失败: {e}")
+        return False
+
+
+def _copy_in_aliyun_oss(src_key, dest_key):
+    bucket = get_oss_client()
+    try:
+        result = bucket.copy_object(src_key, dest_key)
+        return result.status == 200
+    except Exception as e:
+        print(f"阿里云OSS复制失败: {e}")
+        return False
+
+
 def delete_from_oss(file_url):
     """
     从OSS删除文件