This example demonstrates how to set up a message inbox for the Spina Pro CMS, showing a complete workflow for generating a message object and building a submission form. It uses Rails generators and Spina’s `Spina::Pro::Message` base class to define fields like `first_name`, `last_name`, and `email`, while a custom `SampleMessagesController` handles POST requests with Turbo Streams for form updates. The code relies on the `invisible_captcha` gem for spam protection and the `OOPSpam` API for spam scoring. A theme’s contact page embeds the form via a turbo frame, and routes are explicitly drawn under `Spina::Engine.routes.draw` to point to the controller’s `create` action.