chatgui: invite link dialogs, zxing-cpp QR code, crypto transport, channel improvements; msg_transport: chat protocol support

tools/chatgui/src/invitedialog.cpp

@@ -0,0 +1,47 @@
+#include "invitedialog.h"
+#include "qrcode_utils.h"
+#include <QVBoxLayout>
+#include <QHBoxLayout>
+#include <QLineEdit>
+#include <QPushButton>
+#include <QLabel>
+#include <QClipboard>
+#include <QApplication>
+
+InviteDialog::InviteDialog(const QString& link, QWidget* parent)
+    : QDialog(parent), m_link(link)
+{
+    setWindowTitle("Пригласительная ссылка");
+    setMinimumWidth(420);
+    setModal(true);
+
+    auto *layout = new QVBoxLayout(this);
+    layout->setSpacing(12);
+
+    auto *linkEdit = new QLineEdit(m_link, this);
+    linkEdit->setReadOnly(true);
+    linkEdit->setStyleSheet("padding: 6px; font-family: monospace;");
+    layout->addWidget(linkEdit);
+
+    auto *btnLayout = new QHBoxLayout();
+    auto *copyBtn = new QPushButton("Скопировать", this);
+    connect(copyBtn, &QPushButton::clicked, this, [this, linkEdit]() {
+        QApplication::clipboard()->setText(m_link);
+        linkEdit->setFocus();
+    });
+    btnLayout->addWidget(copyBtn);
+    btnLayout->addStretch();
+    layout->addLayout(btnLayout);
+
+    auto *qrLabel = new QLabel(this);
+    QImage qrImage = generateQRCode(m_link);
+    if (!qrImage.isNull())
+        qrLabel->setPixmap(QPixmap::fromImage(qrImage).scaled(
+            180, 180, Qt::KeepAspectRatio, Qt::SmoothTransformation));
+    qrLabel->setAlignment(Qt::AlignCenter);
+    layout->addWidget(qrLabel, 0, Qt::AlignCenter);
+
+    auto *closeBtn = new QPushButton("OK", this);
+    connect(closeBtn, &QPushButton::clicked, this, &QDialog::accept);
+    layout->addWidget(closeBtn, 0, Qt::AlignRight);
+}