feat: add WordPress as runtime — Dockerfile, K8s env vars, wp-content PVC, frontend UI

Backend:
- Add WORDPRESS to AppRuntime enum
- Add wordpressDockerfile() using wordpress:6-php8.3-apache base image
  with custom theme/plugin/wp-content merge support
- Add WordPress-specific K8s env vars (WORDPRESS_DB_HOST, WORDPRESS_DB_USER,
  WORDPRESS_DB_PASSWORD, WORDPRESS_DB_NAME, WORDPRESS_TABLE_PREFIX)
- Create wp-content PersistentVolumeClaim (2Gi) for WordPress deployments
- Mount wp-content PVC in deployment container at /var/www/html/wp-content

Frontend:
- Add 'wordpress' to runtime type unions (Application, CreateApplicationDto)
- Add WordPress runtime card in deploy page (port 80, blue icon)
- Auto-select MySQL database when WordPress is chosen, disable other DB options
- Show Persian hint 'وردپرس به MySQL نیاز دارد' when WordPress selected
- Update all runtime icon colors across dashboard, apps, admin/apps pages
  to show blue-600 for WordPress

frontend/src/app/dashboard/page.tsx

@@ -123,7 +123,7 @@ export default function DashboardPage() {
                 >
                   <div className="flex items-center gap-4">
                     <div className="w-11 h-11 rounded-xl bg-primary-50 flex items-center justify-center shrink-0">
-                      <Hexagon className={`w-5 h-5 ${app.runtime === 'nodejs' ? 'text-green-600' : 'text-orange-500'}`} />
+                      <Hexagon className={`w-5 h-5 ${app.runtime === 'nodejs' ? 'text-green-600' : app.runtime === 'wordpress' ? 'text-blue-600' : 'text-orange-500'}`} />
                     </div>
                     <div className="min-w-0">
                       <h3 className="font-semibold text-gray-900 group-hover:text-primary-700 transition-colors truncate">