ONLYOFFICE/DocumentServer ? reverse-engineered prompt

Build me a self hosted collaborative office suite like ONLYOFFICE Docs that I can run on my own server.

I want people to be able to open and edit Word, Excel, PowerPoint, PDF, forms, and diagram files in the browser, with real time collaboration, comments or review, spell check, and a clean interface that works in multiple languages and dark mode. It should feel like a complete document server I can plug into another app or use on its own.

Please make the project runnable from the repo, with clear startup steps, sane defaults, and a simple way to test that the editors and file conversion are working. If you need to check the latest setup details, look up the current docs online. Also make sure the result is polished enough that someone could self host it without having to figure out the internals first.