chatgui: integrate UtunNode + NodeConfig, replace MsgClient

- Add NodeConfig: simplified INI config manager for embedded uTun node
  - X25519 key generation via OpenSSL EVP
  - Random node_id generation
  - addServer/removeServer, addClient/removeClient API
  - Auto-creates config with default server on first run
- Integrate UtunNode into MainWindow:
  - Creates NodeConfig in ~/.config/chatgui/node.conf
  - Starts embedded uTun node (no TUN, no msg_transport)
  - In separate thread with uasync_poll event loop
- Replace MsgClient (TCP IPC) with UtunNode (direct calls):
  - ChatPropagator now uses UtunNode for send/recv
  - send(uint64_t, QByteArray) replaces sendTo
  - messageReceived signal replaces received signal
- MainWindow cleanup: remove MsgClient, add UtunNode+NodeConfig

tools/chatgui/src/mainwindow.cpp

@@ -5,14 +5,16 @@
 #include "invitedialog.h"
 #include "invite_link.h"
 #include "../db/db_manager.h"
-#include "../transport/msg_client.h"
+#include "../transport/utun_node.h"
+#include "../transport/node_config.h"
 #include "../transport/chat_propagator.h"
-#include "../transport/crypto.h"
 #include <QSplitter>
 #include <QCloseEvent>
 #include <QApplication>
 #include <QStyle>
 #include <QMessageBox>
+#include <QStandardPaths>
+#include <QDir>
 
 MainWindow::MainWindow(QWidget *parent, DbManager* db)
     : QMainWindow(parent)
@@ -22,8 +24,6 @@ MainWindow::MainWindow(QWidget *parent, DbManager* db)
     , m_trayIcon(nullptr)
     , m_trayMenu(nullptr)
     , m_db(db)
-    , m_client(nullptr)
-    , m_propagator(nullptr)
 {
     setWindowTitle("Chat");
     resize(900, 600);
@@ -31,12 +31,8 @@ MainWindow::MainWindow(QWidget *parent, DbManager* db)
     setupTray();
 
     if (m_db && m_db->isOpen()) {
-        m_client     = new MsgClient(this);
-        m_propagator = new ChatPropagator(m_client, m_db, this);
-        m_messageList->setPropagator(m_propagator);
-
-        connect(m_propagator, &ChatPropagator::messageReceived,
-                m_messageList, &MessageList::addMessage);
+        setupNode();
+        setupMessaging();
 
         connect(m_channelList, &ChannelList::channelSelected,
                 this, [this](const QString& channelId) {
@@ -56,6 +52,11 @@ MainWindow::MainWindow(QWidget *parent, DbManager* db)
     }
 }
 
+MainWindow::~MainWindow() {
+    if (m_node) { m_node->stop(); delete m_node; m_node = nullptr; }
+    delete m_config;
+}
+
 void MainWindow::setupUi() {
     auto *splitter = new QSplitter(Qt::Horizontal, this);
 
@@ -76,6 +77,45 @@ void MainWindow::setupUi() {
     setCentralWidget(splitter);
 }
 
+void MainWindow::setupNode() {
+    QString configDir = QStandardPaths::writableLocation(QStandardPaths::AppConfigLocation);
+    QDir().mkpath(configDir);
+    QString configPath = configDir + "/node.conf";
+
+    m_config = new NodeConfig(configPath);
+    if (!m_config->exists()) {
+        if (!m_config->create("chatgui", 1333)) {
+            qWarning("Failed to create node config");
+            return;
+        }
+    } else {
+        m_config->load();
+    }
+
+    m_node = new UtunNode(this);
+    connect(m_node, &UtunNode::error, this, [](const QString& msg) {
+        qWarning("UtunNode error: %s", qPrintable(msg));
+    });
+    connect(m_node, &UtunNode::started, this, []() {
+        qDebug("UtunNode started");
+    });
+    connect(m_node, &UtunNode::stopped, this, []() {
+        qDebug("UtunNode stopped");
+    });
+
+    if (!m_node->start(configPath))
+        qWarning("Failed to start UtunNode");
+}
+
+void MainWindow::setupMessaging() {
+    if (!m_node || !m_node->isRunning()) return;
+    m_propagator = new ChatPropagator(m_node, m_db, this);
+    m_messageList->setPropagator(m_propagator);
+
+    connect(m_propagator, &ChatPropagator::messageReceived,
+            m_messageList, &MessageList::addMessage);
+}
+
 void MainWindow::setupTray() {
     m_trayIcon = new QSystemTrayIcon(this);
     m_trayIcon->setIcon(style()->standardIcon(QStyle::SP_ComputerIcon));
@@ -119,9 +159,12 @@ void MainWindow::onTrayActivated(QSystemTrayIcon::ActivationReason reason) {
 void MainWindow::showInviteDialog(const QString& channelId) {
     if (!m_db || !m_db->isOpen()) return;
 
-    QByteArray pubkey = m_db->getLocalPubkey();
+    QByteArray pubkey;
+    if (m_config && !m_config->pubKey().isEmpty())
+        pubkey = QByteArray::fromHex(m_config->pubKey().toLatin1());
+
     if (pubkey.size() != 32) {
-        QMessageBox::warning(this, "Ошибка", "Не удалось получить публичный ключ узла.");
+        QMessageBox::warning(this, "Error", "Failed to get node public key.");
         return;
     }
 
@@ -129,7 +172,7 @@ void MainWindow::showInviteDialog(const QString& channelId) {
 
     QString link = encodeInviteLink(channelId, pubkey, addrs);
     if (link.isEmpty()) {
-        QMessageBox::warning(this, "Ошибка", "Не удалось сформировать пригласительную ссылку.");
+        QMessageBox::warning(this, "Error", "Failed to create invite link.");
         return;
     }