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/global-not-found.tsx

@@ -25,6 +25,7 @@ const inter = Inter({
 
 export const metadata: Metadata = {
   title: "Seite nicht gefunden",
+  robots: { index: false, follow: false },
 };
 
 export default function GlobalNotFound() {
@@ -47,14 +48,17 @@ export default function GlobalNotFound() {
                   Diesen Weg gibt es hier nicht
                 </h1>
                 <p className="mt-5 max-w-md text-lg leading-relaxed text-anouma-plum">
-                  Die gesuchte Seite konnte nicht gefunden werden. Vielleicht findest du deinen Weg
-                  über die Startseite oder die Angebote weiter.
+                  Diese Seite wurde nicht gefunden. Vielleicht findest du deinen Weg über die
+                  Startseite, die Angebote oder den Kontakt weiter.
                 </p>
                 <div className="mt-8 flex flex-wrap gap-4">
                   <Button href="/">Zur Startseite</Button>
                   <Button href="/angebote" variant="secondary">
                     Angebote ansehen
                   </Button>
+                  <Button href="/kontakt" variant="secondary">
+                    Kontakt
+                  </Button>
                 </div>
               </div>
               <div className="relative mx-auto aspect-square w-full max-w-sm">