VM global_env sync + isomorphic nav store primitives

Reverse hook syncs VM GLOBAL_SET mutations back to global_env so CEK reads
see JIT-written values. Isomorphic nav: store primitives, event-bridge,
client? predicate. Browser JS and bytecode rebuilt.

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

hosts/ocaml/lib/sx_runtime.ml

@@ -50,7 +50,12 @@ let sx_call f args =
     Thunk (l.l_body, local)
   | Continuation (k, _) ->
     k (match args with x :: _ -> x | [] -> Nil)
-  | _ -> raise (Eval_error ("Not callable: " ^ inspect f))
+  | _ ->
+    let nargs = List.length args in
+    let args_preview = if nargs = 0 then "" else
+      let s = String.concat ", " (List.map (fun a -> let s = inspect a in if String.length s > 40 then String.sub s 0 40 ^ ".." else s) args) in
+      " with args=[" ^ s ^ "]" in
+    raise (Eval_error ("Not callable: " ^ inspect f ^ args_preview))
 
 (* Initialize forward ref so primitives can call SX functions *)
 let () = Sx_primitives._sx_call_fn := sx_call