send data 수정 전

// ✅ [4] 현재 이미지 UI에 표시
/*void MainWindow::displayCurrentImage()
{
    if (currentIndex >= 0 && currentIndex < monoPaths.size()) {
        QString monoPath = monoPaths[currentIndex];
        QString colorPath = colorPaths[currentIndex];

        QPixmap monoPixmap(monoPath);
        QPixmap colorPixmap(colorPath);

        qDebug() << "[DISPLAY] MONO:" << monoPath;
        qDebug() << "[DISPLAY] COLOR:" << colorPath;

        // MONO 표시
        if (!monoPixmap.isNull()) {
            QLayout* layoutMono = ui->frame_MONO->layout();
            if (!layoutMono) {
                layoutMono = new QVBoxLayout(ui->frame_MONO);
                layoutMono->setContentsMargins(0, 0, 0, 0);
                ui->frame_MONO->setLayout(layoutMono);
            } else {
                QLayoutItem* item;
                while ((item = layoutMono->takeAt(0)) != nullptr) {
                    delete item->widget();
                    delete item;
                }
            }

            QLabel* labelMono = new QLabel(ui->frame_MONO);
            labelMono->setPixmap(monoPixmap.scaled(360, 360, Qt::KeepAspectRatio, Qt::SmoothTransformation));
            labelMono->setAlignment(Qt::AlignCenter);
            layoutMono->addWidget(labelMono);
        } else {
            qWarning() << "파일 열기 실패: " << monoPath;
        }

        // COLOR 표시
        if (!colorPixmap.isNull()) {
            QLayout* layoutColor = ui->frame_COLOR->layout();
            if (!layoutColor) {
                layoutColor = new QVBoxLayout(ui->frame_COLOR);
                layoutColor->setContentsMargins(0, 0, 0, 0);
                ui->frame_COLOR->setLayout(layoutColor);
            } else {
                QLayoutItem* item;
                while ((item = layoutColor->takeAt(0)) != nullptr) {
                    delete item->widget();
                    delete item;
                }
            }

            QLabel* labelColor = new QLabel(ui->frame_COLOR);
            labelColor->setPixmap(colorPixmap.scaled(360, 360, Qt::KeepAspectRatio, Qt::SmoothTransformation));
            labelColor->setAlignment(Qt::AlignCenter);
            layoutColor->addWidget(labelColor);
        } else {
            qWarning() << "파일 열기 실패: " << colorPath;
        }
    }
}

// ✅ [5] 현재 이미지를 서버로 전송 - JSON 포함 패킷 전송 구조 적용
void MainWindow::sendCurrentImageToServer()
{
    if (currentIndex >= 0 && currentIndex < monoPaths.size()) {
        // [1] MONO 이미지
        QString monoPath = monoPaths[currentIndex];
        QFile monoFile(monoPath);
        if (monoFile.open(QIODevice::ReadOnly)) {
            QByteArray monoData = monoFile.readAll();
            monoFile.close();

            json j;
            j["__META__"]["COLOR"] = 0;  // MONO
            j["__META__"]["SIZE"] = monoData.size();

            SocketManager::instance()->sendPacket(1, 1, 0, j, monoData);
            qDebug() << "[SEND MONO] size:" << monoData.size();
        } else {
            qWarning("MONO 파일 열기 실패: %s", qUtf8Printable(monoPath));
        }

        // [2] COLOR 이미지
        QString colorPath = colorPaths[currentIndex];
        QFile colorFile(colorPath);
        if (colorFile.open(QIODevice::ReadOnly)) {
            QByteArray colorData = colorFile.readAll();
            colorFile.close();

            json j;
            j["__META__"]["COLOR"] = 1;  // COLOR
            j["__META__"]["SIZE"] = colorData.size();

            SocketManager::instance()->sendPacket(1, 1, 0, j, colorData);
            qDebug() << "[SEND COLOR] size:" << colorData.size();
        } else {
            qWarning("COLOR 파일 열기 실패: %s", qUtf8Printable(colorPath));
        }
    }
}*/