franciscoBSalgueiro/en-croissant — reverse-engineered prompt

Build me a polished desktop chess toolkit for serious players that still feels simple to use. I want to be able to connect or import my games from lichess.org and chess.com, save them locally, browse them in a database, and analyze them on a nice chess board.

It should support running more than one chess engine at a time, including normal UCI engines, with an easy way to add, remove, and manage engines and databases without digging through folders. I also want a repertoire area where I can prepare openings, review them, and train them with spaced repetition so the app reminds me what to practice.

Please include position search in the game database, both exact positions and partial piece setups. Make the interface clean, customizable, and beginner friendly, but powerful enough for club players. It should work as a cross platform desktop app. Look up current docs online if you need to.