feat: change application style

- change default dark theme to light
- disable dark mode on windows 10 because Qt's windows 11 theme has bad support on windows 10 (icon display error)
- level required minimum qt version up to 6.5 for color schema.

app/mainwindow.cpp

@@ -51,7 +51,6 @@ MainWindow::MainWindow(QWidget *parent)
     , m_pm(new PlaylistManager(this))
     , m_fileSystemWatcher(new QFileSystemWatcher(this))
 {
-    this->setAttribute(Qt::WA_TranslucentBackground, true);
     // YYC MARK:
     // Blumis set original value is 350 x 330.
     // It is too small for modern device,