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.

landingpage/assets/style.css

@@ -325,3 +325,82 @@ footer nav {
 footer a:hover {
   color: var(--foreground);
 }
+
+.legal-layout {
+  display: grid;
+  gap: 2rem;
+  padding-top: 3rem;
+  padding-bottom: 3rem;
+}
+
+@media (min-width: 1024px) {
+  .legal-layout {
+    grid-template-columns: 220px 1fr;
+  }
+}
+
+.legal-nav {
+  display: flex;
+  flex-direction: column;
+  gap: 0.25rem;
+  font-size: 0.875rem;
+}
+
+.legal-nav-title {
+  margin: 0 0 0.5rem;
+  padding: 0 0.5rem;
+  font-size: 0.75rem;
+  font-weight: 600;
+  letter-spacing: 0.05em;
+  text-transform: uppercase;
+  color: var(--muted-foreground);
+}
+
+.legal-nav a {
+  border-radius: calc(var(--radius) - 2px);
+  padding: 0.375rem 0.5rem;
+}
+
+.legal-nav a:hover,
+.legal-nav a.active {
+  background: var(--muted);
+}
+
+.legal-article h1 {
+  margin: 0 0 0.5rem;
+  font-size: 1.875rem;
+  font-weight: 600;
+}
+
+.legal-updated {
+  margin: 0 0 1.5rem;
+  font-size: 0.875rem;
+  color: var(--muted-foreground);
+}
+
+.legal-section {
+  margin-bottom: 1.75rem;
+}
+
+.legal-section h2 {
+  margin: 0 0 0.75rem;
+  font-size: 1.125rem;
+  font-weight: 600;
+}
+
+.legal-section p,
+.legal-section li {
+  margin: 0 0 0.75rem;
+  font-size: 0.9375rem;
+  color: var(--muted-foreground);
+  line-height: 1.6;
+}
+
+.legal-section ul {
+  margin: 0 0 0.75rem;
+  padding-left: 1.25rem;
+}
+
+.legal-lines {
+  margin-bottom: 0.75rem;
+}