Added licenses and used included headers in minimal examples

Co-authored-by: jpr42 <109434725+jpr42@users.noreply.github.com>

tests/vk_hpp.cpp

@@ -1,6 +1,13 @@
+/*
+ * Copyright 2025 The Khronos Group Inc.
+ * Copyright 2025 Valve Corporation
+ * Copyright 2025 LunarG, Inc.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
 #include <vulkan/vulkan.hpp>
 
-int square(int i)
+int header_version()
 {
-    return i * i;
+    return VK_HEADER_VERSION;
 }