Rewrite Classic ASP Form Handler to Wordpress PHP plugin

Develop a Classic ASP form handler converted into a WordPress PHP plugin that preserves original form behaviour while integrating seamlessly with modern WP environments. Tasks include parsing ASP form submissions, securely mapping fields, recreating validation logic and email notifications. Deliver well-documented, maintainable code with activation/deactivation hooks, compatibility across recent WP versions, live and test modes and clear installation instructions.