Add promise-delayed SSR stub; fix startup JIT DISABLED noise

promise-delayed is a browser-only primitive used by the resource island
demo. The SSR renderer needs it as a stub to avoid "Undefined symbol"
errors during render-to-html JIT compilation.

The stub returns the value argument (skipping the delay), so SSR renders
the resolved state immediately.

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

hosts/ocaml/bin/sx_server.ml

@@ -329,6 +329,8 @@ let setup_browser_stubs env =
   bind "dom-get-data" (fun _args -> Nil);
   bind "event-detail" (fun _args -> Nil);
   bind "promise-then" (fun _args -> Nil);
+  bind "promise-delayed" (fun args ->
+    match args with _ :: [v] -> v | _ -> Nil);
   bind "schedule-idle" (fun _args -> Nil);
   bind "dom-query" (fun _args -> Nil);
   bind "dom-query-all" (fun _args -> List []);