Add Turnstile protection to user actions

app/(frontend)/angebote/[slug]/page.tsx

@@ -22,6 +22,7 @@ import { resolveRedirect } from "@/lib/seo/redirects";
 import { siteConfig } from "@/lib/site";
 
 export const dynamic = "force-dynamic";
+const turnstileSiteKey = process.env.TURNSTILE_SITE_KEY ?? "";
 
 type Args = { params: Promise<{ slug: string }> };
 const WEEKDAY_LABELS: Record<string, string> = { monday: "Montag", tuesday: "Dienstag", wednesday: "Mittwoch", thursday: "Donnerstag", friday: "Freitag", saturday: "Samstag", sunday: "Sonntag" };
@@ -138,7 +139,7 @@ export default async function OfferDetailPage({ params }: Args) {
             )}
             {offer.groupCapacity && <p className="mb-2 text-sm text-anouma-plum/75">Plätze: {offer.groupCapacity}</p>}
             {offer.registrationDeadline && <p className="mb-6 text-sm text-anouma-plum/75">Anmeldung möglich bis {new Date(offer.registrationDeadline).toLocaleDateString("de-DE")}</p>}
-            <GroupRegistrationForm offerSlug={offer.slug!} />
+            <GroupRegistrationForm offerSlug={offer.slug!} siteKey={turnstileSiteKey} />
           </div>
         </Section>
       ) : offer.bookable ? (