Add Stacking Blocks interactive

Add "Stacking Blocks" interactive to the Puzzles page. This new interactive is based on the description provided in the attached screenshots.

src/pages/StackingBlocksPage.tsx

@@ -0,0 +1,29 @@
+import StackingBlocks from "@/components/StackingBlocks";
+import { useSearchParams } from "react-router-dom";
+
+const StackingBlocksPage = () => {
+  const [searchParams] = useSearchParams();
+  const from = searchParams.get('from');
+
+  if (from === 'puzzles') {
+    return (
+      <div className="min-h-screen bg-background">
+        <div className="container mx-auto px-4 py-8 space-y-6">
+          <div className="flex items-center gap-4">
+            <button 
+              onClick={() => window.location.href = '/themes/puzzles'}
+              className="text-primary hover:text-primary/80 font-medium"
+            >
+              ← Back to Puzzles
+            </button>
+          </div>
+          <StackingBlocks showSocialShare={true} />
+        </div>
+      </div>
+    );
+  }
+
+  return <StackingBlocks showSocialShare={true} />;
+};
+
+export default StackingBlocksPage;

src/pages/theme-pages/Puzzles.tsx

@@ -75,6 +75,16 @@ const Puzzles = () => {
       difficulty: "Intermediate" as const,
       duration: "5-15 min",
       participants: "1 player"
+    },
+    {
+      id: "stacking-blocks",
+      title: "Stacking Blocks Optimization",
+      description: "Split stacks of blocks to maximize your score! Each split earns points equal to the product of the new stack sizes.",
+      path: "/puzzles/stacking-blocks",
+      tags: ["Optimization", "Strategy", "Mathematical", "Algorithm"],
+      difficulty: "Intermediate" as const,
+      duration: "10-20 min",
+      participants: "1 player"
     }
   ];