修复编译问题和版本兼容问题

cloudprint-backend/internal/grpc/service/file_service.go

@@ -24,7 +24,6 @@ func NewFileServiceServer(fileService *service.FileService) *FileServiceServer {
 func (s *FileServiceServer) Upload(stream pb.FileService_UploadServer) (*pb.UploadResponse, error) {
 	var fileName, fileType, uploaderType string
 	var uploaderID int32
-	var totalSize int64
 	var chunks [][]byte
 
 	for {
@@ -41,7 +40,6 @@ func (s *FileServiceServer) Upload(stream pb.FileService_UploadServer) (*pb.Uplo
 			fileType = req.FileType
 			uploaderType = "user" // Extract from context in production
 			uploaderID = 1        // Extract from context in production
-			totalSize = req.FileSize
 		}
 
 		chunks = append(chunks, req.Data)