metrics: RTT/loss histograms + Ed25519 signing + peer exchange via INIT handshake + file logging to stats/<peer>.dat

- etcp_metrics struct: 12-bucket RTT histogram, 11-bucket loss histogram, 10-min snapshots (>=200 pkts)
- Total counters: packets/bytes sent/rcvd, losses (retrans + probe gap detection)
- CSV append to <stats_dir>/<peer_id>.dat every 10 min
- Ed25519 pubkey exchange in INIT handshake (V3), always present
- Signed metrics exchange via ETCP_SECTION_METRICS (0x0A)
- Received metrics saved as from_<peer_id>.dat with signature hex
- on_metrics_rcvd callback in ETCP_BINDINGS
- stats_dir derived from config file path, mkdir'd at instance init
- Simplified versioning: ETCP_INIT_REQ_SIZE / ETCP_INIT_RESP_SIZE via sizeof

tools/chatgui/src/mainwindow.cpp

@@ -4,20 +4,19 @@
 #include "accountlist.h"
 #include "invitedialog.h"
 #include "joindialog.h"
+#include "settingsdialog.h"
 #include "invite_link.h"
 #include "../db/db_manager.h"
 #include "../transport/utun_node.h"
-#include "../transport/node_config.h"
 #include "../transport/gui_bridge.h"
 #include <QSplitter>
 #include <QCloseEvent>
 #include <QApplication>
 #include <QStyle>
 #include <QMessageBox>
-#include <QStandardPaths>
-#include <QDir>
 
-MainWindow::MainWindow(QWidget *parent, DbManager* db)
+MainWindow::MainWindow(QWidget *parent, DbManager* db, const QString& cfgPath,
+                       const QString& debugFile)
     : QMainWindow(parent)
     , m_channelList(nullptr)
     , m_messageList(nullptr)
@@ -25,6 +24,8 @@ MainWindow::MainWindow(QWidget *parent, DbManager* db)
     , m_trayIcon(nullptr)
     , m_trayMenu(nullptr)
     , m_db(db)
+    , m_cfgPath(cfgPath)
+    , m_cfgDebugFile(debugFile)
 {
     setWindowTitle("Chat");
     resize(900, 600);
@@ -45,6 +46,8 @@ MainWindow::MainWindow(QWidget *parent, DbManager* db)
                 this, &MainWindow::showInviteDialog);
         connect(m_channelList, &ChannelList::joinRequested,
                 this, &MainWindow::showJoinDialog);
+        connect(m_channelList, &ChannelList::settingsRequested,
+                this, &MainWindow::showSettings);
 
         m_channelList->loadChannels();
         m_accountList->loadAccounts();
@@ -57,7 +60,6 @@ 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() {
@@ -81,20 +83,6 @@ void MainWindow::setupUi() {
 }
 
 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));
@@ -106,7 +94,10 @@ void MainWindow::setupNode() {
         qDebug("UtunNode stopped");
     });
 
-    if (!m_node->start(configPath))
+    if (!m_cfgDebugFile.isEmpty())
+        m_node->setDebugFile(m_cfgDebugFile);
+
+    if (!m_node->start(m_cfgPath))
         qWarning("Failed to start UtunNode");
 }
 
@@ -125,6 +116,11 @@ void MainWindow::setupTray() {
     m_trayIcon->setToolTip("Chat");
 
     m_trayMenu = new QMenu(this);
+    QAction *settingsAction = m_trayMenu->addAction("Settings");
+    connect(settingsAction, &QAction::triggered, this, &MainWindow::showSettings);
+
+    m_trayMenu->addSeparator();
+
     QAction *showAction = m_trayMenu->addAction("Show");
     connect(showAction, &QAction::triggered, this, [this]() {
         show();
@@ -163,8 +159,8 @@ void MainWindow::showInviteDialog(const QString& channelId) {
     if (!m_db || !m_db->isOpen()) return;
 
     QByteArray pubkey;
-    if (m_config && !m_config->pubKey().isEmpty())
-        pubkey = QByteArray::fromHex(m_config->pubKey().toLatin1());
+    if (m_node && m_node->isRunning())
+        pubkey = QByteArray::fromHex(m_node->pubKeyHex().toLatin1());
 
     if (pubkey.size() != 32) {
         QMessageBox::warning(this, "Error", "Failed to get node public key.");
@@ -193,3 +189,8 @@ void MainWindow::showJoinDialog() {
         m_channelList->loadChannels();
     }
 }
+
+void MainWindow::showSettings() {
+    SettingsDialog dlg(m_cfgPath, this);
+    dlg.exec();
+}