fix: 移除上传文件时的多余参数，简化 MinIO 上传逻辑

backend/server/routers/auth_router.py

@@ -758,7 +758,7 @@ async def upload_user_avatar(
 
         # 上传到MinIO
         file_name = f"avatar/{current_user.id}/{uuid.uuid4()}.{file_extension}"
-        avatar_url = await aupload_file_to_minio("public", file_name, file_content, file_extension)
+        avatar_url = await aupload_file_to_minio("public", file_name, file_content)
 
         # 更新用户头像
         current_user.avatar = avatar_url

backend/server/routers/knowledge_router.py

@@ -1334,7 +1334,7 @@ async def upload_file(
     object_name = f"{folder}/upload/{minio_filename}"
 
     # 上传到MinIO
-    minio_url = await aupload_file_to_minio(bucket_name, object_name, file_bytes, ext.lstrip("."))
+    minio_url = await aupload_file_to_minio(bucket_name, object_name, file_bytes)
 
     # 检测同名文件（基于原始文件名）
     same_name_files = await knowledge_base.get_same_name_files(db_id, filename)