Add Qt-only autosave recovery fallback

Provide a small KAutoSaveFile-compatible implementation for the no-KF5 build path and use it to keep the existing crash-recovery code active when BUILD_WITH_KF5=OFF.

The normal KF5 build still uses the KDE KAutoSaveFile implementation.

Assisted-by: pi coding agent / Mika (OpenAI GPT-5.5)

sources/qetproject.h

@@ -30,6 +30,7 @@
 #include "titleblockproperties.h"
 
 #ifdef BUILD_WITHOUT_KF5
+#	include "ui/nokde/kautosavefile.h"
 #else
 #	include <KAutoSaveFile>
 #endif
@@ -48,10 +49,6 @@ class XmlElementCollection;
 class QTimer;
 class TerminalStrip;
 
-#ifdef BUILD_WITHOUT_KF5
-#else
-class KAutoSaveFile;
-#endif
 
 /**
 	This class represents a QET project. Typically saved as a .qet file, it
@@ -79,10 +76,7 @@ class QETProject : public QObject
 	public:
 		QETProject (QObject *parent = nullptr);
 		QETProject (const QString &path, QObject * = nullptr);
-#ifdef BUILD_WITHOUT_KF5
-#else
 		QETProject (KAutoSaveFile *backup, QObject *parent=nullptr);
-#endif
 		~QETProject() override;
 
 	private:
@@ -297,10 +291,7 @@ class QETProject : public QObject
 		QTimer m_save_backup_timer,
 			   m_autosave_timer;
 		QFuture<bool> m_backup_future;
-#ifdef BUILD_WITHOUT_KF5
-#else
 		KAutoSaveFile m_backup_file;
-#endif
 		QUuid m_uuid = QUuid::createUuid();
 		projectDataBase m_data_base;
 		QVector<TerminalStrip *> m_terminal_strip_vector;