refactor: improve header imports and forward declarations

src/MainWindow.cpp

@@ -201,4 +201,4 @@ void MainWindow::setupTrayIcon()
 
 MainWindow::~MainWindow()
 {
-}
+}

src/MainWindow.h

@@ -7,8 +7,10 @@
 
 #include <QMainWindow>
 
+QT_BEGIN_NAMESPACE
 class QSvgWidget;
 class QSystemTrayIcon;
+QT_END_NAMESPACE
 
 class MainWindow : public QMainWindow
 {

src/VerticalLabel.cpp

@@ -3,6 +3,8 @@
 //
 
 #include "VerticalLabel.h"
+#include <QPainter>
+
 VerticalLabel::VerticalLabel(const QString &text, QWidget *parent) : QLabel(text, parent)
 {
 

src/VerticalLabel.h

@@ -6,7 +6,6 @@
 #define LLINK_VERTICALLABEL_H
 
 #include <QLabel>
-#include <QPainter>
 
 class VerticalLabel : public QLabel
 {