Fix root cause: skip JIT for closure lambdas in BOTH hook and vm_call

The closure check was only in vm_call (sx_vm.ml) but inner functions
like read-list-loop were also compiled through the JIT hook in
sx_server.ml. The hook compiled them with closure merging, producing
incorrect bytecode (read-list-loop mishandled closing parens).

Added the same closure check to the JIT hook: skip lambdas with
non-empty closures. Now sx-parse works correctly:
  (a (b) (c)) → 3 siblings, not (a (b (c)))

Pre-compiled count increased from 17 to 33 — more top-level
functions compiled (inner ones correctly skipped to CEK).

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

hosts/ocaml/bin/sx_server.ml

@@ -913,6 +913,10 @@ let register_jit_hook env =
        | Some _ -> None  (* compile failed — CEK handles *)
        | None ->
          if !_jit_compiling then None
+         else if Hashtbl.length l.l_closure.bindings > 0
+                 || l.l_closure.parent <> None then
+           (* Skip JIT for lambdas with closure bindings *)
+           None
          else begin
            let fn_name = match l.l_name with Some n -> n | None -> "?" in
            _jit_compiling := true;

shared/sx/ocaml_bridge.py

@@ -440,16 +440,6 @@ class OcamlBridge:
                         _logger.warning("OCaml load skipped %s: %s",
                                         filepath, e)
 
-                # JIT workaround: sx-parse has a complex letrec (20 mutually
-                # recursive functions) that the JIT compiles incorrectly —
-                # closing parens cause siblings to become children.
-                # CEK-interpreted sx-parse works correctly.
-                try:
-                    await self._send('(vm-reset-fn "sx-parse")')
-                    await self._read_until_ok(ctx=None)
-                except OcamlBridgeError:
-                    pass
-
                 # SSR overrides: effect is a no-op on the server (prevents
                 # reactive loops during island SSR — effects are DOM side-effects)
                 try: