Contact
This is a portfolio project rather than a company, so there is no support desk. What follows is every way to reach it or to act without reaching it.
Deleting your data
You do not have to ask. The account page deletes your account and everything reachable from it — workspaces, documents, the text and passages extracted from them, and every conversation. It happens immediately and no copy is kept.
Documents held in your browser by local mode never reached a server, so no request here can remove them. Clear them from that page.
Questions, and anything deletion does not cover
Open an issue on the repository. It is public, so write nothing there you would not publish — for anything that has to stay private, say so in the issue and a route will be arranged.
What this project will never send you
The only email it sends is a sign-in link, and only when somebody asks for one. There is no newsletter, no product mail, and no address list.