feat: implement configurable font settings for VTK viewports and GUI elements with persistent preferences.

app/gcompose/src/main.cpp

@@ -3,6 +3,8 @@
 #include "MainPanel.h"
 #include "ViewportPane.h"
 #include "StyleManager.h"
+#include "Settings.h"
+#include "Core/FontConfig.h"
 
 #include "Math/ContainerBox.h"
 #include <HEP/Geant/Scene.h>
@@ -29,7 +31,9 @@ using namespace uLib::literals;
 
 int main(int argc, char** argv) {
     QApplication app(argc, argv);
-    StyleManager::applyStyle(&app, "dark");
+    auto theme = uLib::Qt::Settings::Instance().GetTheme();
+    auto initialGuiFont = uLib::Qt::Settings::Instance().GetGuiFont();
+    StyleManager::applyStyle(&app, theme == uLib::Qt::Settings::Dark ? "dark" : "bright", initialGuiFont);
     std::cout << "Starting gcompose Qt application..." << std::endl;
 
     // ContainerBox world_box(Vector3f(1, 1, 1));