Security improvements:
- Add explicit returns after wp_send_json_error() in AJAX handlers
- Add JSON error handling with json_last_error_msg()
- Add CSS sanitization to prevent injection in fonts and components
- Use WP_Filesystem for safer file operations in components
- Add path traversal protection in Task Manager with realpath validation
- Add slug format validation in Task Manager
- Add .htaccess protection for tasks directory

Performance improvements:
- Add batch limiting (100 posts) to Link Management database updates
- Add has_more flag for pagination in bulk updates
- Add filter for customizing batch limit: functionalities_link_update_batch_limit