Fix server import suspension, dist sync, JIT errors

- cek_run patched to handle import suspensions via _import_hook.
  define-library (import ...) now resolves cleanly on the server.
  IO suspension errors: 190 → 0. JIT failures: ~50 → 0.
- _import_hook wired in sx_server.ml to load .sx files on demand.
- compile-modules.js syncs source .sx files to dist/sx/ before
  compiling — eliminates stale bytecode from out-of-date copies.
- WASM binary rebuilt with all fixes.
- 2658/2658 tests pass (8 new — previously failing import tests).

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

hosts/ocaml/lib/sx_ref.ml

@@ -488,7 +488,21 @@ and cek_step_loop state =
 
 (* cek-run *)
 and cek_run state =
-  (let final = (cek_step_loop (state)) in (if sx_truthy ((cek_suspended_p (final))) then (raise (Eval_error (value_to_str (String "IO suspension in non-IO context")))) else (cek_value (final))))
+  (let rec run s =
+    let final = cek_step_loop s in
+    if sx_truthy (cek_suspended_p final) then begin
+      let request = cek_io_request final in
+      let op = match request with Dict d -> (match Hashtbl.find_opt d "op" with Some (String s) -> s | _ -> "") | _ -> "" in
+      if op = "import" then
+        let lib_spec = match request with Dict d -> (match Hashtbl.find_opt d "library" with Some v -> v | _ -> Nil) | _ -> Nil in
+        let key = library_name_key lib_spec in
+        let resolved = sx_truthy (library_loaded_p key) ||
+          (match !_import_hook with Some hook -> hook lib_spec | None -> false) in
+        if resolved then run (cek_resume final Nil)
+        else raise (Eval_error "IO suspension in non-IO context")
+      else raise (Eval_error "IO suspension in non-IO context")
+    end else cek_value final
+  in run state)
 
 (* cek-resume *)
 and cek_resume suspended_state result' =
@@ -815,7 +829,26 @@ let cek_run_iterative state =
       s := cek_step !s
     done;
     (match cek_suspended_p !s with
-     | Bool true -> raise (Eval_error "IO suspension in non-IO context")
+     | Bool true ->
+       let request = cek_io_request !s in
+       let op = match request with Dict d -> (match Hashtbl.find_opt d "op" with Some (String s) -> s | _ -> "") | _ -> "" in
+       if op = "import" then begin
+         let lib_spec = match request with Dict d -> (match Hashtbl.find_opt d "library" with Some v -> v | _ -> Nil) | _ -> Nil in
+         let key = library_name_key lib_spec in
+         let resolved = sx_truthy (library_loaded_p key) ||
+           (match !_import_hook with Some hook -> hook lib_spec | None -> false) in
+         if resolved then begin
+           s := cek_resume !s Nil;
+           (* Continue the step loop after resolving the import *)
+           while not (match cek_terminal_p !s with Bool true -> true | _ -> false)
+              && not (match cek_suspended_p !s with Bool true -> true | _ -> false) do
+             s := cek_step !s
+           done;
+           (match cek_suspended_p !s with
+            | Bool true -> raise (Eval_error "IO suspension in non-IO context")
+            | _ -> cek_value !s)
+         end else raise (Eval_error "IO suspension in non-IO context")
+       end else raise (Eval_error "IO suspension in non-IO context")
      | _ -> cek_value !s)
   with Eval_error msg ->
     _last_error_kont_ref := cek_kont !s;