feat: auto-hide controls in full screen, add subtitle size and outline settings

src/qml/Main.qml

@@ -18,6 +18,7 @@ Kirigami.ApplicationWindow {
     pageStack.initialPage: PlayerPage {
         id: player
         initialUrl: root.initialUrl
+        fullScreen: root.visibility === Window.FullScreen
         onAboutRequested: root.pageStack.layers.push(aboutPage)
         onSettingsRequested: root.pageStack.layers.push(settingsPage)
         onFullScreenToggled: root.visibility = root.visibility === Window.FullScreen ? Window.Windowed : Window.FullScreen