Prep Plugin for release on WordPress.org

Escape everything that should be escaped.
Add nonce checks where needed.
Sanitize all inputs.
Apply Code style changes across the codebase.
Correct many deprecation notices.
Optimize load order of many filters.

inc/admin-pages/class-domain-list-admin-page.php

@@ -196,7 +196,7 @@ class Domain_List_Admin_Page extends List_Admin_Page {
 				'field_wrapper_classes' => 'wu-w-full wu-box-border wu-items-center wu-flex wu-justify-between wu-p-4 wu-m-0 wu-border-t wu-border-l-0 wu-border-r-0 wu-border-b-0 wu-border-gray-300 wu-border-solid',
 				'html_attr'             => [
 					'data-wu-app' => 'add_new_domain',
-					'data-state'  => json_encode(
+					'data-state'  => wp_json_encode(
 						[
 							'type'           => 'add',
 							'primary_domain' => false,