Chess Game Builder Computer Opponent

♟️ Build your own chess game with Claude Code – your pieces, your board, your colors. ♚ Full rules: castling, en passant, promotion, all draw types 🧠 Built-in computer opponent with 5 levels + hint arrows ⏱️ Clocks with increment, 2-player mode, undo, review 📋 SAN move list, PGN and FEN copy, FEN loading 📱 Drag, tap or keyboard play on phone + desktop 🧪 Self-test with perft counts: every check must PASS 📄 One offline HTML file, no chess libraries