Add Cynthia Trenshaw Poetry link to navigation

- Add external link to cynthia-staging.jeffemmett.com
- Support external links in both desktop and mobile nav
- Opens in new tab with proper rel attributes

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/src/components/navigation.tsx

@@ -28,6 +28,7 @@ const navLinks = [
   { href: '/about', label: 'About' },
   { href: '/contact', label: 'Contact' },
   { href: '/subscribe', label: 'Subscribe' },
+  { href: 'https://cynthia-staging.jeffemmett.com', label: 'Cynthia Trenshaw Poetry', external: true },
 ];
 
 const socialLinks = [
@@ -173,6 +174,16 @@ export function Navigation() {
                       </div>
                     )}
                   </div>
+                ) : 'external' in link && link.external ? (
+                  <a
+                    key={link.href}
+                    href={link.href}
+                    target="_blank"
+                    rel="noopener noreferrer"
+                    className="text-sm tracking-wide opacity-80 hover:opacity-100 transition-opacity"
+                  >
+                    {link.label}
+                  </a>
                 ) : (
                   <Link
                     key={link.href}
@@ -230,6 +241,17 @@ export function Navigation() {
                       ))}
                     </div>
                   </div>
+                ) : 'external' in link && link.external ? (
+                  <a
+                    key={link.href}
+                    href={link.href}
+                    target="_blank"
+                    rel="noopener noreferrer"
+                    className="block py-2 text-sm text-gray-700"
+                    onClick={() => setMobileMenuOpen(false)}
+                  >
+                    {link.label}
+                  </a>
                 ) : (
                   <Link
                     key={link.href}