feat: add searchable dropdown with Popover + Command pattern

Rewrite SelectField to use shadcn/ui Popover + Command (cmdk) pattern
for searchable selects, following best practices. This eliminates
console errors from the previous input-inside-SelectContent approach.

Changes:
- SelectField.js: Use Popover + Command for searchable fields
- Add Command component with CommandInput for proper search
- Update dialog.jsx to use Huge Icons instead of lucide-react
- Simplify searchable logic to follow PHP config directly

The Command component handles keyboard navigation and filtering
properly without focus event conflicts.

build/admin.asset.php

@@ -1 +1 @@
-<?php return array('dependencies' => array('react', 'react-dom', 'wp-components', 'wp-element', 'wp-i18n', 'wp-icons/build/arrow-left', 'wp-icons/build/bell', 'wp-icons/build/message', 'wp-icons/build/trash'), 'version' => '79dab88e37717bf64790');
+<?php return array('dependencies' => array('react', 'react-dom', 'wp-components', 'wp-element', 'wp-i18n', 'wp-icons/build/arrow-left', 'wp-icons/build/bell', 'wp-icons/build/message', 'wp-icons/build/trash'), 'version' => 'e564b3f018fca608f7b7');