niedev/RTranslator ? reverse-engineered prompt

Build me an Android app called RTranslator that can translate speech in real time completely on the phone, so it works offline and keeps conversations private.

I want three main modes. One mode should let two people have a back and forth conversation, using the phone mic or a Bluetooth headset, then turn speech into text, translate it, and speak the result out loud on the other phone. Another mode should be a quick walkie talkie style translator for two people using one phone, where each person speaks in turn and the app listens, translates, and reads the reply aloud. The third mode should be a simple text translator with copy and speak buttons.

Make it feel polished and easy to use, with a clean modern interface, language selection, status feedback, and support for background use when possible. If you need to check the latest docs or model details online, go ahead and do that. Also make sure the app handles downloading the needed AI models on first launch and gives clear guidance if the user wants to sideload them.