Method buildApdTab

src/gui/RadioSetupDialog.cpp:3525–3604

// reports this; older firmware and 6000-series radios stay hidden.

QWidget* RadioSetupDialog::buildApdTab()
{
    auto* page = new QWidget;
    auto* vbox = new QVBoxLayout(page);
    vbox->setSpacing(8);

    // Model header — matches other tabs (e.g. Filters, TX)
    {
        auto* hdr = new QHBoxLayout;
        hdr->addStretch(1);
        auto* modelLbl = new QLabel(m_model->model());
        AetherSDR::ThemeManager::instance().applyStyleSheet(modelLbl, "QLabel { color: {{color.accent.bright}}; font-size: 20px; font-weight: bold; }");
        hdr->addWidget(modelLbl);
        vbox->addLayout(hdr);
    }

    auto& tx = m_model->transmitModel();

    // External Sampler group — 2-column grid: ANT1/XVTA on the top row,
    // ANT2/XVTB on the bottom row, then the Reset button on its own row.
    {
        auto* group = new QGroupBox("External Sampler (per TX ANT)");
        group->setStyleSheet(kGroupStyle);
        auto* grid = new QGridLayout(group);
        grid->setSpacing(8);

        // Row, col-pair, antenna name → builds label + combo, hooks signals.
        auto buildRow = [&](int row, int colBase, const QString& ant) {
            auto* lbl = new QLabel(ant + ":");
            lbl->setStyleSheet(kLabelStyle);
            grid->addWidget(lbl, row, colBase);

            auto* combo = new QComboBox;
            const auto s = tx.apdSampler(ant);
            combo->addItems(s.available);
            combo->setCurrentText(s.selected);
            AetherSDR::applyComboStyle(combo);
            grid->addWidget(combo, row, colBase + 1);

            m_apdSamplerCombos.insert(ant, combo);

            connect(combo, &QComboBox::currentTextChanged, this,
                    [this, ant](const QString& port) {
                if (port.isEmpty()) return;
                m_model->transmitModel().setApdSamplerPort(ant, port);
            });
        };

        buildRow(0, 0, "ANT1");
        buildRow(0, 2, "XVTA");
        buildRow(1, 0, "ANT2");
        buildRow(1, 2, "XVTB");

        // Equalizer Reset button (row 2) — clears all per-antenna training.
        auto* resetLbl = new QLabel("Equalizer Reset:");
        resetLbl->setStyleSheet(kLabelStyle);
        grid->addWidget(resetLbl, 2, 0);