Add English and Russian ChatGUI interface translations

tools/chatgui/transport/node_config.cpp

@@ -1,6 +1,7 @@
 // node_config.cpp — Simplified INI config manager for embedded uTun node
 #include "node_config.h"
 #include "config_updater.h"
+#include "../../../lib/debug_config.h"
 #include <QHostInfo>
 
 extern "C" {
@@ -39,7 +40,7 @@ static const QSet<QString> CONTROL_KEYS = {
 };
 
 static const QSet<QString> GUI_KEYS = {
-    "db_path", "debug_file", "debug_level",
+    "db_path", "debug_file", "debug_level", "language",
     "sound_dir", "sound_msg_incoming", "sound_msg_outgoing",
     "sound_connect", "sound_disconnect"
 };
@@ -225,6 +226,7 @@ bool NodeConfig::load() {
     m_servers.clear();
     m_clients.clear();
     m_errors.clear();
+    m_language = QStringLiteral("system");
 
     QString section, controlIp, controlPort;
     QTextStream in(&f);
@@ -336,6 +338,10 @@ bool NodeConfig::load() {
             if (key == "db_path") m_dbPath = val;
             else if (key == "debug_file") m_debugFile = val;
             else if (key == "debug_level") m_debugLevel = val;
+            else if (key == "language") {
+                if (val == "system" || val == "en" || val == "ru") m_language = val;
+                else DEBUG_WARN(DEBUG_CATEGORY_CONFIG, "GUI language: invalid preference '%s', using system language", qPrintable(val));
+            }
         } else if (debugSection) {
             if (!m_debugCategories.isEmpty()) m_debugCategories += ',';
             m_debugCategories += key + '=' + val;
@@ -386,6 +392,7 @@ bool NodeConfig::saveFull() {
     out << "[gui]\n";
     out << "db_path=" << (m_dbPath.isEmpty() ? "chat_data" : m_dbPath) << "\n";
     out << "debug_file=" << m_debugFile << "\n";
+    out << "language=" << m_language << "\n";
     out << "debug_level=" << (m_debugLevel.isEmpty() ? "info" : m_debugLevel) << "\n\n";
 
     out << "[debug]\n";
@@ -445,6 +452,7 @@ bool NodeConfig::save() {
 
     config_update_in_lines(lines, "gui", "db_path", m_dbPath.isEmpty() ? "chat_data" : m_dbPath, true);
     config_update_in_lines(lines, "gui", "debug_file", m_debugFile, true);
+    config_update_in_lines(lines, "gui", "language", m_language, true);
     config_update_in_lines(lines, "gui", "debug_level", m_debugLevel.isEmpty() ? "info" : m_debugLevel, true);
 
     /* [debug] section: each category=level as separate line */