Update legal documents and localization for compliance and clarity

- Updated .env.example with legal operator details for compliance.
- Refactored Impressum, Privacy, and Terms pages to utilize a new LegalDocument component for improved structure and maintainability.
- Enhanced localization files to include legal content in both German and English, ensuring accurate representation of legal information.
- Improved i18n handling to support locale detection from Accept-Language headers.

apps/webui/src/app/terms/page.tsx

@@ -1,3 +1,4 @@
+import { LegalDocument } from '@/components/site/legal-document';
 import { LegalShell } from '@/components/site/legal-shell';
 import { getLocale, t } from '@/lib/i18n';
 
@@ -6,12 +7,7 @@ export default async function TermsPage() {
 
   return (
     <LegalShell title={t(locale, 'legal.terms.title')}>
-      <p className="text-sm text-amber-600 dark:text-amber-400">{t(locale, 'legal.scaffoldNotice')}</p>
-      {['p1', 'p2', 'p3', 'p4'].map((key) => (
-        <p key={key} className="text-sm text-muted-foreground">
-          {t(locale, `legal.terms.${key}`)}
-        </p>
-      ))}
+      <LegalDocument locale={locale} page="terms" />
     </LegalShell>
   );
 }