feat: plakat redesign phase 4 (chat window, contact, footer, cleanup) (#77)

- AI chat moves into a window/sheet, opened from a new speech-bubble card on
  the desk; it now respects the chatbot consent and asks before sending
  anything to n8n (previously it ignored the consent)
- Contact as red poster section with big mail address and the form on a paper
  card; validation errors are finally shown inline (aria-invalid, role=alert)
- Footer as ink strip with dk0 wordmark, legal links and a button to reopen
  the privacy settings
- "About me" in the header opens the about window on the home page
- Remove the old About section and its parts (BentoChat, ActivityFeed,
  CurrentlyReading, ReadBooks), the unused ChatWidget, Projects and BentoGrid,
  their tests, wrappers, loaders, types and texts
- scripts/directus-cleanup-redesign.mjs: dry run by default, --apply archives
  hobbies, tech stack categories and old content pages and deletes four
  unused message overrides after a full JSON backup; run only after the
  redesign is live on production

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

app/components/tisch/TischSection.tsx

@@ -45,6 +45,8 @@ export default async function TischSection({ locale }: TischSectionProps) {
     bookLabel: t("bookLabel"),
     bookFallback: t("bookFallback"),
     photoCaption: t("photoCaption"),
+    chatCard: t("chatCard"),
+    chatCardHint: t("chatCardHint"),
     sticker: t("sticker"),
   };
 
@@ -73,6 +75,7 @@ export default async function TischSection({ locale }: TischSectionProps) {
     { kind: "server", id: "server" },
     { kind: "book", id: "book", href: `/${locale}/books` },
     { kind: "photo", id: "photo" },
+    { kind: "chat", id: "chat" },
     { kind: "sticker", id: "sticker" },
   ];
   // Im Stapel wäre der runde Sticker eine Ellipse und wiederholt nur den Claim