fix another ABI break

Author: ethanglaser

include/svs/orchestrators/vamana.h

@@ -50,9 +50,6 @@ class VamanaInterface {
 
     virtual size_t get_graph_max_degree() const = 0;
 
-    ///// Memory accounting
-    virtual svs::index::vamana::MemoryBreakdown get_memory_breakdown() const = 0;
-
     virtual void set_construction_window_size(size_t window_size) = 0;
     virtual size_t get_construction_window_size() const = 0;
 
@@ -104,6 +101,12 @@ class VamanaInterface {
 
     // Non-templated virtual method for distance calculation
     virtual double get_distance(size_t id, const AnonymousArray<1>& query) const = 0;
+
+    ///// Memory accounting
+    // New virtuals belong at the end of the interface: inserting one shifts every
+    // later vtable slot, and a consumer built against the old header then dispatches
+    // through the wrong slot with no link-time diagnostic.
+    virtual svs::index::vamana::MemoryBreakdown get_memory_breakdown() const = 0;
 };
 
 template <lib::TypeList QueryTypes, typename Impl, typename IFace = VamanaInterface>
@@ -130,10 +133,6 @@ class VamanaImpl : public manager::ManagerImpl<QueryTypes, Impl, IFace> {
 
     size_t get_graph_max_degree() const override { return impl().get_graph_max_degree(); }
 
-    svs::index::vamana::MemoryBreakdown get_memory_breakdown() const override {
-        return impl().get_memory_breakdown();
-    }
-
     void set_construction_window_size(size_t window_size) override {
         impl().set_construction_window_size(window_size);
     }
@@ -274,6 +273,11 @@ class VamanaImpl : public manager::ManagerImpl<QueryTypes, Impl, IFace> {
             }
         );
     }
+
+    ///// Memory accounting
+    svs::index::vamana::MemoryBreakdown get_memory_breakdown() const override {
+        return impl().get_memory_breakdown();
+    }
 };
 
 ///// Forward declarations