hivepress/hivepress-messages ? reverse-engineered prompt

Build me a WordPress plugin extension for HivePress that lets users send private messages to each other inside a directory or listings site.

I want logged in users to be able to start conversations, reply back and forth, and see a simple inbox and message thread view in their account area. It should feel like a clean add on for HivePress, not a separate app, and it should fit the style of a classifieds or marketplace site. If there are any HivePress hooks or current WordPress best practices I should follow, look them up online and use the right approach.

Please make it work with the latest supported WordPress and PHP versions, keep it lightweight, and structure it so it would be easy to maintain as an extension. Include the basic templates, the main plugin file, and whatever else is needed so the messaging feature is usable right away.