Add mobile swipe gallery, shared ProductCard, dynamic Datenschutz address, GSC verification

- ProductGallery: touch swipe (left/right) now navigates slides on mobile,
  previously click-only.
- New shared ProductCard component used by ProductGrid/RelatedProducts/
  MerklisteGrid — product title is now the card's link (replaces the
  separate "Mehr erfahren" line), consistent aspect ratio across all
  three grids, more compact cards.
- Datenschutz: name/address/email now come from company-settings via a
  new VerantwortlicherBlock, same single-source pattern as Impressum's
  AnbieterAngaben — no more hand-typed address to keep in sync.
- layout.tsx: render googleSearchConsoleVerification via Next's native
  verification.google metadata field.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

app/datenschutz/components/VerantwortlicherBlock.tsx

@@ -0,0 +1,54 @@
+import { headingId } from "../../components/RichText";
+import type { CompanySettings } from "../../lib/payload";
+import type { TOCSection } from "../../components/SectionTOC";
+
+// Renders "1. Verantwortlicher" straight from company-settings, same
+// single-source-of-truth pattern as Impressum's AnbieterAngaben.tsx — this
+// used to be hand-typed name/address/email baked into the Datenschutz
+// richText (seed-datenschutz.ts on the Payload side), silently out of
+// date the moment company-settings changed without a matching manual
+// edit here too. The heading itself stays numbered "1." (headingId's own
+// `^(\d+)\.` match turns that into "section-1", exactly the id this
+// section's TOC entry already had before the RichText stopped rendering
+// it — no anchor breakage).
+export function verantwortlicherHeadings(): TOCSection[] {
+  return [{ id: headingId("1. Verantwortlicher"), title: "1. Verantwortlicher" }];
+}
+
+function Heading({ children }: { children: string }) {
+  return (
+    <h2
+      id={headingId(children)}
+      className="font-semibold text-h-small text-text-primary mt-2 scroll-mt-32 first:mt-0"
+      style={{ fontFamily: "var(--font-lora)" }}
+    >
+      {children}
+      <span className="block h-[0.125rem] w-8 bg-brand mt-2" aria-hidden />
+    </h2>
+  );
+}
+
+function P({ children }: { children: React.ReactNode }) {
+  return <p className="text-body text-text-body">{children}</p>;
+}
+
+export function VerantwortlicherBlock({ seller }: { seller: CompanySettings }) {
+  return (
+    <div className="flex flex-col gap-4 w-full">
+      <Heading>1. Verantwortlicher</Heading>
+      <P>Verantwortlich für die Datenverarbeitung auf dieser Website ist:</P>
+      <div className="flex flex-col gap-1">
+        <P>{seller.managingDirector || seller.sellerName}</P>
+        <P>{seller.sellerStreet}</P>
+        <P>
+          {seller.sellerZip} {seller.sellerCity}
+        </P>
+        <P>{seller.sellerCountry}</P>
+        <P>
+          E-Mail: <a href={`mailto:${seller.sellerEmail}`} className="text-brand hover:underline">{seller.sellerEmail}</a>
+        </P>
+      </div>
+      <P>Ein gesetzlich vorgeschriebener Datenschutzbeauftragter ist für unser Unternehmen aufgrund seiner Größe derzeit nicht erforderlich.</P>
+    </div>
+  );
+}