Test Qt-only autosave recovery fallback

Add a no-KF5 Catch regression test that leaves a KAutoSaveFile-compatible backup behind from a child process, then verifies stale-file discovery, stale-lock recovery, reading, and cleanup.

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

tests/catch/CMakeLists.txt

@@ -83,6 +83,20 @@ add_executable(
     ${QET_DIR}/sources/borderproperties.h
     )
 
+if(NOT BUILD_WITH_KF5)
+    target_sources(
+        ${PROJECT_NAME}
+        PRIVATE
+        src/kautosavefile_test.cpp
+        ${QET_DIR}/sources/ui/nokde/kautosavefile.cpp
+        )
+    target_include_directories(
+        ${PROJECT_NAME}
+        PRIVATE
+        ${QET_DIR}/sources/ui/nokde
+        )
+endif()
+
 target_link_libraries(
     ${PROJECT_NAME}
     PUBLIC