xo-object: improve GC unittest + prep to integrate w/ xo::reflect

include/xo/alloc/generation.hpp

@@ -0,0 +1,26 @@
+/* generation.hpp
+ *
+ * author: Roland Conybeare, Aug 2025
+ */
+
+#include <cstdint>
+
+namespace xo {
+    namespace gc {
+        enum class generation {
+            nursery,
+            tenured,
+            N
+        };
+
+        constexpr std::size_t gen2int(generation x) { return static_cast<std::size_t>(x); }
+
+        enum class generation_result {
+            nursery,
+            tenured,
+            not_found
+        };
+    } /*namespace gc*/
+} /*namespace xo*/
+
+/* end generation.hpp */