Add NightShot source

include/settings_window.hpp

@@ -0,0 +1,13 @@
+#pragma once
+
+#include "config.hpp"
+
+#include <windows.h>
+
+namespace settings_window {
+
+void show(HWND owner);
+[[nodiscard]] bool handleDialogMessage(MSG* message);
+[[nodiscard]] HWND window();
+
+} // namespace settings_window