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/components/site/legal-document.tsx

@@ -0,0 +1,47 @@
+import { MESSAGES, type Locale } from '@/lib/i18n';
+
+type LegalSection = {
+  heading?: string;
+  paragraphs?: string[];
+  lines?: string[];
+  list?: string[];
+};
+
+export function LegalDocument({
+  locale,
+  page
+}: {
+  locale: Locale;
+  page: 'impressum' | 'privacy' | 'terms';
+}) {
+  const legal = MESSAGES[locale].legal[page];
+  const sections = legal.sections as LegalSection[];
+
+  return (
+    <>
+      <p className="text-sm text-muted-foreground">{MESSAGES[locale].legal.updated}</p>
+      {sections.map((section) => (
+        <section key={section.heading} className="space-y-3">
+          {section.heading ? <h2 className="text-lg font-semibold">{section.heading}</h2> : null}
+          {section.paragraphs?.map((paragraph) => (
+            <p key={paragraph.slice(0, 48)} className="text-sm leading-relaxed text-muted-foreground">
+              {paragraph}
+            </p>
+          ))}
+          {section.lines && section.lines.length > 0 ? (
+            <p className="whitespace-pre-line text-sm leading-relaxed text-muted-foreground">
+              {section.lines.join('\n')}
+            </p>
+          ) : null}
+          {section.list && section.list.length > 0 ? (
+            <ul className="list-disc space-y-1 pl-5 text-sm leading-relaxed text-muted-foreground">
+              {section.list.map((item) => (
+                <li key={item.slice(0, 48)}>{item}</li>
+              ))}
+            </ul>
+          ) : null}
+        </section>
+      ))}
+    </>
+  );
+}