Zero bootstrap patches: all 11 moved to spec or runtime

- make-raise-guard-frame: was never defined in spec — added it
- *last-error-kont*: set at error origination (host-error calls), not
  wrapped around every cek-run step. Zero overhead on normal path.
- JIT: jit-try-call runtime function called from spec. Platform
  registers hook via _jit_try_call_fn ref. No bootstrap patching.
- bootstrap.py compile_spec_to_ml() now returns transpiled output
  with zero post-processing.

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

hosts/ocaml/lib/sx_runtime.ml

@@ -474,3 +474,16 @@ let debug_log _ _ = Nil
 (* mutable_list — mutable list for bytecode compiler pool entries *)
 let mutable_list () = ListRef (ref [])
 
+(* JIT try-call — ref set by sx_server.ml after compiler loads.
+   Returns Nil (no JIT) or the result value. Spec calls this. *)
+let _jit_try_call_fn : (value -> value list -> value option) option ref = ref None
+let jit_try_call f args =
+  match !_jit_try_call_fn with
+  | None -> Nil
+  | Some hook ->
+    match f with
+    | Lambda l when l.l_name <> None ->
+      let arg_list = match args with List a | ListRef { contents = a } -> a | _ -> [] in
+      (match hook f arg_list with Some result -> result | None -> Nil)
+    | _ -> Nil
+