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/config.ts

@@ -0,0 +1,36 @@
+import { getSEOSettingsGlobal } from "@/lib/payload/globals";
+import { siteConfig } from "@/lib/site";
+
+function stripTrailingSlash(url: string): string {
+  return url.replace(/\/+$/, "");
+}
+
+/**
+ * The canonical base URL for the whole site. Prefers the CMS override
+ * (SEO-Einstellungen → Website-URL) when it's a valid absolute URL, then
+ * NEXT_PUBLIC_SERVER_URL (the single source of truth used everywhere else
+ * in this app — emails, meeting links, Payload's own serverURL), then the
+ * hardcoded siteConfig fallback. Never throws — SEO metadata must never
+ * break a page render.
+ */
+export async function getSiteUrl(): Promise<string> {
+  try {
+    const settings = await getSEOSettingsGlobal();
+    if (settings.siteUrl && /^https?:\/\/.+/.test(settings.siteUrl)) {
+      return stripTrailingSlash(settings.siteUrl);
+    }
+  } catch {
+    // CMS/DB unreachable — fall through to the env-based default.
+  }
+  return stripTrailingSlash(process.env.NEXT_PUBLIC_SERVER_URL || siteConfig.domain);
+}
+
+/** Whether the site should be indexable at all (global kill switch in the CMS). */
+export async function isSiteIndexable(): Promise<boolean> {
+  try {
+    const settings = await getSEOSettingsGlobal();
+    return settings.robotsIndexable !== false;
+  } catch {
+    return true;
+  }
+}