christophersutton/platica ? reverse-engineered prompt

Build me a modern real time chat app for workplaces called Platica.

I want a clean web app where people can sign in, join conversations, send messages instantly, and upload files. It should have a frontend and a backend, with a simple local setup using Bun, TypeScript, and React. Use SQLite for the database and make file uploads work with S3 compatible storage. Please set it up so I can run the whole thing locally with one dev command, and also have setup commands for the database and sample data.

Make the app feel polished and easy to use, with a straightforward chat experience that works well for teams. If you need to check current docs online for Bun or any related tools, go ahead and do that. Also include sensible environment settings, build and test scripts, and keep the code organized so it is easy to extend later.