FEAT(client): Automatically sync theme with OS color scheme- v4

This update introduces an automatic theme switch that changes based on the OS color scheme at startup and during runtime. This feature is implemented for Qt 6.2 and includes compatibility for Qt 6.5 once Mumble upgrades.

Implements mumble-voip#6515

src/mumble/MainWindow.cpp

@@ -86,16 +86,6 @@
 #	include <dbt.h>
 #endif
 
-
-#include <QFile>
-#include <QGuiApplication>
-#include <QPalette>
-#include <QSettings>
-#include <QStyleHints>
-#include <QTextStream>
-
-
-
 #include <algorithm>
 
 MessageBoxEvent::MessageBoxEvent(QString m) : QEvent(static_cast< QEvent::Type >(MB_QEVENT)) {
@@ -208,7 +198,6 @@ MainWindow::MainWindow(QWidget *p)
 					 &PluginManager::on_serverSynchronized);
 
 	QAccessible::installFactory(AccessibleSlider::semanticSliderFactory);
-
 }
 
 void MainWindow::createActions() {