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>

lib/seo/metadata.ts

@@ -0,0 +1,52 @@
+import type { Metadata } from "next";
+import { siteConfig } from "@/lib/site";
+import { getSiteUrl, isSiteIndexable } from "./config";
+
+/**
+ * Single shared Metadata builder used by every public page's
+ * generateMetadata — guarantees every page gets its own canonical, robots,
+ * Open Graph and Twitter/X card data instead of copy-pasted boilerplate
+ * (and the accidental duplicate-description bugs that come with that).
+ *
+ * `path` is the page's path relative to the site root (e.g.
+ * "/angebote/doula-begleitung", or "" for the homepage).
+ */
+export async function buildMetadata(args: {
+  title: string;
+  description: string;
+  path: string;
+  ogImageUrl?: string;
+  keywords?: string;
+  noindex?: boolean;
+  type?: "website" | "article";
+}): Promise<Metadata> {
+  const [siteUrl, sitewideIndexable] = await Promise.all([getSiteUrl(), isSiteIndexable()]);
+  const canonical = `${siteUrl}${args.path}`;
+  const indexable = !args.noindex && sitewideIndexable;
+  const images = args.ogImageUrl ? [{ url: args.ogImageUrl }] : undefined;
+
+  return {
+    title: args.title,
+    description: args.description,
+    keywords: args.keywords,
+    alternates: { canonical },
+    robots: indexable
+      ? { index: true, follow: true }
+      : { index: false, follow: false },
+    openGraph: {
+      title: args.title,
+      description: args.description,
+      url: canonical,
+      siteName: siteConfig.name,
+      type: args.type ?? "website",
+      images,
+      locale: siteConfig.locale,
+    },
+    twitter: {
+      card: images ? "summary_large_image" : "summary",
+      title: args.title,
+      description: args.description,
+      images: images?.map((image) => image.url),
+    },
+  };
+}