feat(marketing): add captioned product walkthrough video

src/app/page.tsx

@@ -40,6 +40,7 @@ import {
 } from "@/lib/marketing/seo";
 import { ProductScreenshots, ScreenshotPreview } from "@/components/marketing/product-screenshots";
 import { getProductScreenshot } from "@/lib/marketing/screenshots";
+import { ProductVideo } from "@/components/marketing/product-video";
 import { ContactForm } from "./contact-form";
 
 export const metadata = publicPageMetadata(
@@ -244,10 +245,10 @@ export default function LandingPage() {
                   size="lg"
                   className="h-12 bg-white px-6 text-slate-950 hover:bg-white/90"
                 >
-                  <Link href="/#kontakt">
-                    Demo anfragen
+                  <a href="#produkt-video">
+                    Video ansehen
                     <ArrowRight className="h-4 w-4" />
-                  </Link>
+                  </a>
                 </Button>
                 <Button
                   asChild
@@ -271,6 +272,8 @@ export default function LandingPage() {
           </div>
         </section>
 
+        <ProductVideo />
+
         <section className="mx-auto w-full max-w-7xl px-5 py-20 sm:px-6 lg:py-24">
           <div className="mb-10 grid gap-5 lg:grid-cols-[0.78fr_1fr] lg:items-end">
             <div>