feat: German as the main language, English under /en, with a language switch

The site now exists in German (at the root, with /impressum and /datenschutz)
and English (/en). A request without a language follows the visitor's choice
from the language switch, then the browser language, then German; the old
English legal addresses move to /en for good.

All visible texts are data in src/content/de.ts and en.ts, so components hold
none of their own. The header carries a DE/EN switch whose bit curtain covers
the page while it is swapped and reopens at the same reading position. Title,
description, canonical, hreflang, Open Graph, the share image, the sitemap and
the structured data are per language. The privacy notice now describes the
cookie that remembers the chosen language.

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

apps/web/src/components/home/ContactComposer.tsx

@@ -1,7 +1,7 @@
 "use client";
 
 import * as React from "react";
-import { CONTACT_TOPICS } from "@/src/content/contact";
+import { useContent } from "@/src/components/ContentProvider";
 import { CONTACT_EMAIL_PARTS } from "@/src/content/site";
 import { assembleEmail, mailtoHref, spellOutEmail } from "@/src/domain/email";
 
@@ -51,7 +51,9 @@ const withBlanks = (text: string): React.ReactNode =>
  * is assembled in the browser, so it never appears in the page source.
  */
 export const ContactComposer: React.FC = () => {
-  const [topicId, setTopicId] = React.useState(CONTACT_TOPICS[0]?.id ?? "");
+  const { contact } = useContent();
+  const topics = contact.topics;
+  const [topicId, setTopicId] = React.useState(topics[0]?.id ?? "");
   const [address, setAddress] = React.useState<string | null>(null);
   const [copied, setCopied] = React.useState(false);
 
@@ -59,8 +61,7 @@ export const ContactComposer: React.FC = () => {
     setAddress(assembleEmail(CONTACT_EMAIL_PARTS));
   }, []);
 
-  const topic =
-    CONTACT_TOPICS.find((item) => item.id === topicId) ?? CONTACT_TOPICS[0];
+  const topic = topics.find((item) => item.id === topicId) ?? topics[0];
   const typed = useTyped(topic?.draft.body ?? "");
 
   if (!topic) return null;
@@ -87,18 +88,18 @@ export const ContactComposer: React.FC = () => {
             <span className="h-2.5 w-2.5 rounded-full bg-slate-700" />
             <span className="h-2.5 w-2.5 rounded-full bg-slate-700" />
           </span>
-          <span className={`${MONO} text-slate-400`}>New message</span>
+          <span className={`${MONO} text-slate-400`}>{contact.newMessage}</span>
         </div>
         <span className={`${MONO} flex items-center gap-2 text-slate-500`}>
           <span className="h-1.5 w-1.5 animate-pulse rounded-full bg-emerald-400" />
-          draft
+          {contact.draft}
         </span>
       </div>
 
       <div className="border-b border-slate-800 px-5 py-5 md:px-7">
-        <p className={`${MONO} m-0 text-slate-500`}>I need</p>
+        <p className={`${MONO} m-0 text-slate-500`}>{contact.need}</p>
         <div className="mt-3 flex flex-wrap gap-2">
-          {CONTACT_TOPICS.map((item) => {
+          {topics.map((item) => {
             const selected = item.id === topic.id;
             return (
               <button
@@ -121,13 +122,13 @@ export const ContactComposer: React.FC = () => {
 
       <dl className="m-0 border-b border-slate-800 px-5 py-4 font-mono text-[12px] leading-relaxed md:px-7 md:text-[13px]">
         <div className="flex gap-4">
-          <dt className="w-16 shrink-0 text-slate-500">to</dt>
+          <dt className="w-16 shrink-0 text-slate-500">{contact.to}</dt>
           <dd className="m-0 select-all text-slate-200">
             {address ?? spellOutEmail(CONTACT_EMAIL_PARTS)}
           </dd>
         </div>
         <div className="mt-1 flex gap-4">
-          <dt className="w-16 shrink-0 text-slate-500">subject</dt>
+          <dt className="w-16 shrink-0 text-slate-500">{contact.subject}</dt>
           <dd className="m-0 text-white">{topic.draft.subject}</dd>
         </div>
       </dl>
@@ -150,7 +151,7 @@ export const ContactComposer: React.FC = () => {
           }
           className="bit-cta bit-cta-light group inline-flex flex-1 items-center justify-between gap-4 rounded-full bg-white px-7 py-4 font-sans text-[12px] font-bold uppercase tracking-[0.18em] text-slate-900 no-underline transition-transform duration-300 hover:-translate-y-0.5"
         >
-          Open in my mail app
+          {contact.open}
           <span
             aria-hidden="true"
             className="transition-transform duration-300 group-hover:translate-x-1"
@@ -163,7 +164,7 @@ export const ContactComposer: React.FC = () => {
           onClick={copy}
           className="rounded-full border border-slate-700 px-6 py-4 font-sans text-[12px] font-bold uppercase tracking-[0.18em] text-slate-300 transition-colors duration-200 hover:border-slate-400 hover:text-white"
         >
-          {copied ? "Copied" : "Copy address"}
+          {copied ? contact.copied : contact.copy}
         </button>
       </div>
     </div>