nokonoko/uguu ? reverse-engineered prompt

Build me a simple temporary file sharing site like Uguu, with a clean modern homepage where people can upload files in one click, no account needed. It should support dragging files in, pasting screenshots, and regular click to upload, plus an API that can return results as JSON, HTML, plain text, or CSV. I also want it to work nicely with ShareX and similar screenshot tools.

Please include the basic safety features too, like file type and extension checks, upload rate limiting, and a way to block specific files by hash. Keep it lightweight and easy to run with Nginx and PHP, and use a database like SQLite if that makes sense. If you need to look up current docs online while wiring it up, go ahead. I care more about it feeling fast and simple than adding a lot of extra stuff.