web/DownloadButton: show a message about ongoing antibot check

web/src/components/save/buttons/DownloadButton.svelte

@@ -6,6 +6,9 @@
     import { createDialog } from "$lib/dialogs";
     import { downloadFile } from "$lib/download";
 
+    import { cachedInfo } from "$lib/api/server-info";
+    import { turnstileLoaded } from "$lib/state/turnstile";
+
     import type { DialogInfo } from "$lib/types/dialog";
 
     export let url: string;
@@ -63,6 +66,15 @@
     export const download = async (link: string) => {
         changeDownloadButton("think");
 
+        if ($cachedInfo?.info?.cobalt?.turnstileSitekey && !$turnstileLoaded) {
+            changeDownloadButton("error");
+
+            return createDialog({
+                ...defaultErrorPopup,
+                bodyText: $t("error.captcha_ongoing"),
+            });
+        }
+
         const response = await API.request(link);
 
         if (!response) {