launcher: configure and preview DualSense lightbar color (#912)

launcher: configure and preview controller lightbar color

Add an optional lightbar color to launcher settings and pass it to the emulator with --controller-color. Preview changes on RGB gamepads, handle controller hotplug events, and restore the saved color when settings dialogs close. Release launcher preview handles when starting a game.

Co-authored-by: m66401970-eng <m66401970@gmail.com>

src/launcher/include/configurationEditDialog.h

@@ -31,6 +31,9 @@ public:
 	void                      SetGameDirectories(const QStringList& dirs);
 	[[nodiscard]] QStringList GetGameDirectories() const;
 
+signals:
+	void PreviewControllerColor(const QString& color);
+
 private:
 	Ui::ConfigurationEditDialog* m_ui = nullptr;
 	Configuration&               m_info;