CekState record optimization + profiling: 1.5x speedup, root cause found

Transpiler (transpiler.sx): detects CEK state dict literals (5 fields:
control/env/kont/phase/value) and emits CekState OCaml record instead
of Dict(Hashtbl). Eliminates 200K Hashtbl allocations per page.

Bootstrapper: skip stdlib.sx (functions already registered as OCaml
primitives). Only transpile evaluator.sx.

Runtime: get_val handles CekState with direct field access. type_of
returns "dict" for CekState (backward compat).

Profiling results (root cause of slowness):
  Pure eval: OCaml 1.6x FASTER than Python (expected)
  Aser: OCaml 28x SLOWER than Python (unexpected!)

Root cause: Python has a native optimized aser. OCaml runs the SX
adapter-sx.sx through the CEK machine — each aserCall is ~50 CEK
steps with closures, scope operations, string building.

Fix needed: native OCaml aser (like Python's), not SX adapter
through CEK machine.

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

hosts/ocaml/bin/sx_server.ml

@@ -724,7 +724,7 @@ let dispatch env cmd =
     (try
       ignore (env_bind env "expand-components?" (NativeFn ("expand-components?", fun _args -> Bool true)));
       (* Enable batch IO mode *)
-      io_batch_mode := true;
+      io_batch_mode := true; Sx_ref._cek_steps := 0;
       io_queue := [];
       io_counter := 0;
       let exprs = Sx_parser.parse_all src in
@@ -749,8 +749,8 @@ let dispatch env cmd =
       (* Flush batched IO: send requests, receive responses, replace placeholders *)
       let final = flush_batched_io result_str in
       let t2 = Unix.gettimeofday () in
-      Printf.eprintf "[aser-slot] eval=%.1fs io_flush=%.1fs batched=%d result=%d chars\n%!"
-        (t1 -. t0) (t2 -. t1) n_batched (String.length final);
+      Printf.eprintf "[aser-slot] eval=%.1fs io_flush=%.1fs batched=%d result=%d chars cek_steps=%d\n%!"
+        (t1 -. t0) (t2 -. t1) n_batched (String.length final) !Sx_ref._cek_steps;
       send (Printf.sprintf "(ok-raw %s)" final)
     with
     | Eval_error msg ->