feat: Adressbuch-Block mit Suche, Org- und Buchstabenfilter

- AdressbuchBlock: listet alle Kontakte alphabetisch mit Suche,
  Org-Filter-Chips und A–Z-Buchstabenfilter; /adressbuch-Seite
- ContactCard: neues Design passend zu OrganisationsCard (Badges, Links)
- ContactsBlock: Karussell mit snap-scroll, volle Breite
- block-types, blog-utils, cms: AdressbuchBlockData, resolveAdressbuchBlocks,
  getContacts; BlockRenderer registriert adressbuch
- Kontakt-Seite: Link auf /adressbuch statt eingebettetem Block

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/lib/blog-utils.ts

@@ -8,6 +8,7 @@ import {
   getEntryBySlug,
   getCalendarBySlug,
   getCalendarItemBySlug,
+  getContacts,
   getCalendarItems,
 } from "./cms";
 import type { RowContentLayout } from "./block-types";
@@ -833,3 +834,29 @@ export async function resolveStellingnahmeGeneratorBlocks(
     }
   }
 }
+
+export async function resolveAdressbuchBlocks(
+  layout: RowContentLayout | null | undefined,
+): Promise<void> {
+  if (!layout) return;
+  const rows = [layout.row1Content ?? [], layout.row2Content ?? [], layout.row3Content ?? []];
+  let contacts: unknown[] | null = null;
+  for (const content of rows) {
+    if (!Array.isArray(content)) continue;
+    for (const item of content) {
+      if (typeof item !== "object" || item === null) continue;
+      if ((item as { _type?: string })._type !== "adressbuch") continue;
+      if (contacts === null) contacts = await getContacts();
+      const block = item as Record<string, unknown>;
+      const exclude = (block.excludeContacts as unknown[]) ?? [];
+      const excludeSlugs = new Set(
+        exclude.map((e) =>
+          typeof e === "string" ? e : (e as { _slug?: string })?._slug ?? ""
+        ).filter(Boolean)
+      );
+      block.resolvedContacts = excludeSlugs.size
+        ? contacts.filter((c) => !excludeSlugs.has((c as { _slug?: string })._slug ?? ""))
+        : contacts;
+    }
+  }
+}