Method onWaterfallRowReady

src/core/TciServer.cpp:1906–1961

// ── Waterfall row → TCI binary spectrum frames (type=4) ──────────────────────

void TciServer::onWaterfallRowReady(quint32 streamId, const QVector<float>& binsDbm,
                                    double lowMhz, double highMhz,
                                    quint32 timecode, qint64 emittedNs)
{
    Q_UNUSED(timecode); Q_UNUSED(emittedNs);

    bool anySpectrum = false;
    for (const auto& cs : m_clients) {
        if (cs.spectrumEnabled) { anySpectrum = true; break; }
    }
    if (!anySpectrum) return;

    const int nBins = binsDbm.size();
    if (nBins == 0) return;

    // Resolve waterfall streamId → TRX for multi-pan disambiguation.
    // Waterfall IDs are 0x42xx; each PanadapterModel knows its wfStreamId().
    int trx = 0;
    if (m_model) {
        for (auto* pan : m_model->panadapters()) {
            if (pan->wfStreamId() == streamId) {
                for (auto* s : m_model->slices()) {
                    if (s->panId() == pan->panId()) {
                        trx = TciProtocol::tciTrxForSlice(m_model, s);
                        break;
                    }
                }
                break;
            }
        }
    }

    // TciAudioHeader (64 bytes) + float32 dBm bins.
    // type=4 (SPECTRUM, AetherSDR extension — not in TCI spec v2.0).
    // reserved[0] = low edge in Hz, reserved[1] = high edge in Hz.
    QByteArray frame(static_cast<int>(sizeof(TciAudioHeader)) + nBins * static_cast<int>(sizeof(float)),
                     Qt::Uninitialized);

    TciAudioHeader hdr{};
    hdr.receiver    = static_cast<quint32>(trx);
    hdr.format      = 3;      // float32
    hdr.length      = static_cast<quint32>(nBins);
    hdr.type        = 4;      // SPECTRUM (AetherSDR extension)
    hdr.channels    = 1;
    hdr.reserved[0] = static_cast<quint32>(lowMhz  * 1'000'000.0);
    hdr.reserved[1] = static_cast<quint32>(highMhz * 1'000'000.0);
    std::memcpy(frame.data(), &hdr, sizeof(hdr));

    auto* dst = reinterpret_cast<float*>(frame.data() + sizeof(hdr));
    std::memcpy(dst, binsDbm.constData(), nBins * sizeof(float));

    for (auto& cs : m_clients) {
        if (cs.spectrumEnabled)
            cs.socket->sendBinaryMessage(frame);
    }
}

// ── DAX channel management for TCI audio (#1331) ─────────────────────────────