Modernize plugin with React settings page and PHP 7.4+

[kraftbj]

Summary

• Updates minimum requirements to WordPress 6.0+ and PHP 7.4+
• Adds modern React-based settings page using @wordpress/components
• Modernizes PHP codebase with strict types, typed properties, and arrow functions
• Adds REST API for settings management
• Includes wp-env configuration for easy local development

Changes

New Requirements

• WordPress 6.0+
• PHP 7.4+
• Tested up to WordPress 6.9

Settings Page

• Moved from Settings > Writing to dedicated Settings > Press This page
• Built with React using @wordpress/components (Card, CheckboxControl, SelectControl, etc.)
• Save button shows "Saved!" feedback for 2 seconds after successful save
• REST API endpoint at /press-this-extended/v1/settings

PHP Modernization

• Added declare(strict_types=1)
• Used typed properties and return type declarations
• Replaced anonymous functions with arrow functions
• Removed load_plugin_textdomain() (automatic since WP 4.6)

Development

• Added @wordpress/build for asset compilation
• Added @wordpress/env for local development
• Run pnpm install && pnpm build to build assets
• Run pnpm env:start to start local WordPress environment (includes Press This plugin)

Test plan

• Install on WordPress 6.0+ with PHP 7.4+
• Navigate to Settings > Press This
• Verify all settings load correctly
• Change settings and click Save - verify "Saved!" appears on button
• Verify settings persist after page reload
• Test with Press This plugin to verify filters still work