floor(0)=-1 bug fixed + 12/12 adapter compiles + primitives

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

hosts/ocaml/lib/sx_vm.ml

@@ -246,7 +246,12 @@ let rec run vm =
       let args = List.init argc (fun _ -> pop vm) |> List.rev in
       let result =
         try
-          (match Sx_primitives.get_primitive name with
+          (* Check globals first (has env bindings like set-render-active!),
+             then fall back to registered primitives *)
+          let fn_val = try Hashtbl.find vm.globals name with Not_found ->
+            Sx_primitives.get_primitive name
+          in
+          (match fn_val with
            | NativeFn (_, fn) -> fn args
            | _ -> Nil)
         with Eval_error msg ->