feat: version selection for runtimes and databases

Backend:
- Add runtimeVersion, phpVersion, dbVersion columns to Application entity
- Add version fields to CreateApplicationDto with validation
- Node.js Dockerfile: use selected version (22/20/18/16) instead of hardcoded 20
- Laravel Dockerfile: use selected PHP version (8.4/8.3/8.2/8.1) instead of 8.3
- WordPress Dockerfile: use selected WP version (6.7/6.6/6.5/6.4) + PHP version
- K8s deployDatabase(): use selected DB version instead of hardcoded postgres:16/mysql:8.0
- K8s restoreDatabaseDump(): match DB image version for restore jobs
- Add dbVersion to ManifestContext interface

Frontend:
- Add runtimeVersion, phpVersion, dbVersion to Application and CreateApplicationDto
- Deploy page: Node.js version dropdown (22/20/18/16)
- Deploy page: Laravel PHP version dropdown (8.4/8.3/8.2/8.1)
- Deploy page: WordPress version + PHP version dropdowns
- Deploy page: PostgreSQL version dropdown (17/16/15/14)
- Deploy page: MySQL version dropdown (9.0/8.4/8.0/5.7)
- Deploy page: auto-set default versions on runtime/DB selection
- Review step: show selected versions
- App detail page: display runtime + DB versions in config and header

frontend/src/app/dashboard/apps/[id]/page.tsx

@@ -368,7 +368,7 @@ export default function AppDetailPage() {
               </span>
             </div>
             <p className="text-sm text-gray-500 truncate">
-              {app.runtime} · {app.subdomain}.apps.cloudhost.local
+              {app.runtime}{app.runtimeVersion ? ` v${app.runtimeVersion}` : ''}{app.phpVersion ? ` — PHP ${app.phpVersion}` : ''} · {app.subdomain}.apps.cloudhost.local
             </p>
           </div>
         </div>
@@ -419,11 +419,19 @@ export default function AppDetailPage() {
           <dl className="space-y-3">
             <div className="flex justify-between">
               <dt className="text-sm text-gray-500">Runtime</dt>
-              <dd className="text-sm font-medium text-gray-900">{app.runtime}</dd>
+              <dd className="text-sm font-medium text-gray-900">
+                {app.runtime}
+                {app.runtime === 'nodejs' && app.runtimeVersion ? ` v${app.runtimeVersion}` : ''}
+                {app.runtime === 'wordpress' && app.runtimeVersion ? ` v${app.runtimeVersion}` : ''}
+                {(app.runtime === 'laravel' || app.runtime === 'wordpress') && app.phpVersion ? ` — PHP ${app.phpVersion}` : ''}
+              </dd>
             </div>
             <div className="flex justify-between">
               <dt className="text-sm text-gray-500">Database</dt>
-              <dd className="text-sm font-medium text-gray-900">{app.databaseType}</dd>
+              <dd className="text-sm font-medium text-gray-900">
+                {app.databaseType}
+                {app.databaseType !== 'none' && app.dbVersion ? ` v${app.dbVersion}` : ''}
+              </dd>
             </div>
             <div className="flex justify-between">
               <dt className="text-sm text-gray-500">Replicas</dt>