Fix license headers

src/qt_common/qt_applet_util.cpp

@@ -1 +1,4 @@
+// SPDX-FileCopyrightText: Copyright 2025 Eden Emulator Project
+// SPDX-License-Identifier: GPL-3.0-or-later
+
 #include "qt_applet_util.h"

src/qt_common/qt_applet_util.h

@@ -1,3 +1,6 @@
+// SPDX-FileCopyrightText: Copyright 2025 Eden Emulator Project
+// SPDX-License-Identifier: GPL-3.0-or-later
+
 #ifndef QT_APPLET_UTIL_H
 #define QT_APPLET_UTIL_H