ppareit/swiftp — reverse-engineered prompt

Build me a simple Android app that lets someone turn their phone into an FTP server so they can move files to and from the device over the local network.

I want it to feel like a normal phone app, with a clear screen showing whether the FTP server is running, a big start and stop control, the server address people should type into their computer, and basic settings like username, password, port, and which folder is shared. It should be practical and reliable, not fancy.

Please make it work as an Android project in Java, with sensible defaults and permission handling for storage and networking. Include enough in app help so a non technical user understands how to connect from another device. If you need details about modern Android permissions or FTP behavior, look up current docs online and use the safest approach.