android-sms-gateway/server ? reverse-engineered prompt

Build me a backend for an SMS gateway that lets me send SMS and MMS messages through connected Android phones from a simple REST API. I want users to be able to create and manage devices, send messages right away or schedule them, check delivery status, cancel sends, and view inbox, logs, and settings. It should support login with basic auth and JWT tokens, with permissions for different actions, plus token refresh and revocation.

I also need health check endpoints, webhook support, and a way to run it in both public and private modes. In private mode, device registration should be protected with a token, and in public mode it can be open. Use a MySQL or MariaDB database, include config through a YAML file and environment variables, and make it work well in Docker with a separate worker process for cleanup and background tasks. If you need anything unclear, look up the current docs online first.