Add email verification, personal calendar feed, and full SEO implementation

- Customer accounts now require email verification (hashed, single-use,
  time-limited tokens) before they can request/confirm bookings, with
  resend flows on login/account/booking widget and rate limiting.
- Admins get a private, rotatable iCalendar (ICS) subscription feed of
  their confirmed bookings and public events, timezone-correct for
  Europe/Berlin including DST, never exposing meeting passwords.
- Adds a full SEO layer: per-page canonical/OG/Twitter metadata with
  CMS-editable overrides and content-derived fallbacks, a dynamic
  sitemap.xml and robots.txt driven by real published content, JSON-LD
  (Organization/LocalBusiness, WebSite, WebPage, BreadcrumbList, Service,
  Event, BlogPosting) that never fabricates data, and a CMS-managed
  redirect table for changed slugs.
- Global ANOUMA-naming audit: the brand name is never used to label
  personal account/calendar areas anywhere in the app, CMS, or emails.

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

app/(frontend)/datenschutz/page.tsx

@@ -3,14 +3,19 @@ import { PageHeader } from "@/components/PageHeader";
 import { Section } from "@/components/Section";
 import { PlaceholderNote } from "@/components/PlaceholderNote";
 import { getContactGlobal } from "@/lib/payload/globals";
+import { getSiteUrl } from "@/lib/seo/config";
 
 export const dynamic = "force-dynamic";
 
-export const metadata: Metadata = {
-  title: "Datenschutz",
-  description: "Datenschutzerklärung von Anouma.",
-  robots: { index: false, follow: true },
-};
+export async function generateMetadata(): Promise<Metadata> {
+  const siteUrl = await getSiteUrl();
+  return {
+    title: "Datenschutz",
+    description: "Datenschutzerklärung von Anouma.",
+    robots: { index: false, follow: true },
+    alternates: { canonical: `${siteUrl}/datenschutz` },
+  };
+}
 
 export default async function DatenschutzPage() {
   const contact = await getContactGlobal();