feat: encoding accessor in foundry & less constrained forge setup

Allow forge setup to be called on nullptr and have an empty constructor
setup. Useful to build up forge vectors in one pass instead of add/setup
loops.

eo/src/eoAlgoFoundry.h

@@ -62,6 +62,11 @@ class eoAlgoFoundry : public eoAlgo<EOT>
             return _size;
         }
 
+        std::vector<size_t> encoding() const
+        {
+            return _encoding;
+        }
+
     protected:
         const size_t _size;
         std::vector<size_t> _encoding;