Add Chessboard Repaint Puzzle - a challenging parity puzzle

src/pages/theme-pages/Puzzles.tsx

@@ -16,6 +16,16 @@ const Puzzles = () => {
       duration: "10-30 min",
       participants: "1 player"
     },
+    {
+      id: "chessboard-repaint",
+      title: "Chessboard Repaint Puzzle",
+      description: "Repaint rows, columns, or 2×2 squares to achieve exactly one black square. A puzzle about parity and operations!",
+      path: "/puzzles/chessboard-repaint",
+      tags: ["Logic", "Parity", "Operations"],
+      difficulty: "Advanced" as const,
+      duration: "15-45 min",
+      participants: "1 player"
+    },
     {
       id: "knights-puzzle",
       title: "Knights Exchange Puzzle",