Add Turnstile protection to user actions

app/(frontend)/termine/[slug]/beitreten/page.tsx

@@ -8,6 +8,7 @@ import { combineDateAndTime } from "@/lib/meeting/status";
 import { formatBerlinDate, formatBerlinTime } from "@/lib/calendar/timezone";
 
 export const dynamic = "force-dynamic";
+const turnstileSiteKey = process.env.TURNSTILE_SITE_KEY ?? "";
 
 export const metadata: Metadata = {
   title: "Meeting beitreten",
@@ -42,7 +43,7 @@ export default async function BeitretenPage({ params }: Args) {
         </p>
 
         <div className="mt-10 rounded-[2rem] bg-white/70 p-8 text-left shadow-sm backdrop-blur">
-          <JoinForm slug={slug} />
+          <JoinForm slug={slug} siteKey={turnstileSiteKey} />
         </div>
       </div>
     </section>

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

@@ -25,6 +25,7 @@ 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 }> };
 
@@ -137,7 +138,7 @@ export default async function EventDetailPage({ params }: Args) {
               <div>
                 <h2 className="font-serif text-2xl font-medium text-anouma-plum">Anmeldung</h2>
                 <div className="mt-4 max-w-sm">
-                  <RegisterForm slug={slug} />
+                  <RegisterForm slug={slug} siteKey={turnstileSiteKey} />
                 </div>
               </div>
             )}