xo-alloc2: + missing setup .*pp files

include/xo/alloc2/SetupAlloc2.hpp

@@ -0,0 +1,18 @@
+/** @file SetupAlloc2.hpp
+ *
+ *  @author Roland Conybeare, Feb 2026
+ **/
+
+#pragma once
+
+namespace xo {
+    namespace mm {
+        class SetupAlloc2 {
+        public:
+            /** Register alloc2 (facet,impl) combinations with Facet Registry **/
+            static bool register_facets();
+        };
+    }
+}
+
+/* end SetupAlloc2.hpp */

src/alloc2/SetupAlloc2.cpp

@@ -0,0 +1,33 @@
+/** @file SetupAlloc2.cpp
+ *
+ * @author Roland Conybeare, Feb 2026
+ **/
+
+#include "SetupAlloc2.hpp"
+#include <xo/alloc2/Arena.hpp>
+#include <xo/facet/FacetRegistry.hpp>
+#include <xo/indentlog/scope.hpp>
+
+namespace xo {
+    using xo::facet::FacetRegistry;
+    //using xo::facet::TypeRegistry;
+    using xo::reflect::typeseq;
+
+    namespace mm {
+
+        bool
+        SetupAlloc2::register_facets()
+        {
+            scope log(XO_DEBUG(true));
+
+            FacetRegistry::register_impl<AAllocator, DArena>();
+
+            log && log(xtag("DArena.tseq", typeseq::id<DArena>()));
+
+            return true;
+        }
+
+    } /*namespace scm*/
+} /*namespace xo*/
+
+/* end SetupAlloc2.cpp */