Method cleanup

tests/fl/system/file_system.cpp:65–69

private:
    void cleanup() {
        // Force remove entire directory tree to handle any leftover state
        // This ensures cleanup even if subdirectories/files exist from failed runs
        fl::StubFileSystem::forceRemoveDirectory(mDir.c_str());
    }
};

FL_TEST_CASE("FileSystem test with real hard drive") {