Add interactive to index

Update width and add Sikinia Parliament puzzle to index page.

src/components/SikiniaParliamentPuzzle.tsx

@@ -221,7 +221,7 @@ const SikiniaParliamentPuzzle: React.FC<SikiniaParliamentPuzzleProps> = ({ showS
   };
 
   return (
-    <div className="min-h-screen bg-background p-6 space-y-6">
+    <div className="max-w-4xl mx-auto p-6 space-y-6">
       <Card>
         <CardHeader>
           <div className="flex items-center justify-between">

src/pages/Index.tsx

@@ -76,6 +76,13 @@ const allInteractives = [{
   tags: ['strategy', 'two-player', 'math', 'logic', 'xor-strategy', 'educational'],
   path: '/games/assisted-nim',
   theme: 'Games'
+}, {
+  id: 'sikinia-parliament',
+  title: 'Parliament of Sikinia Puzzle',
+  description: 'Separate parliament members into two houses so each has at most one enemy in their house. A graph theory puzzle!',
+  tags: ['graph-theory', 'logic', 'coloring'],
+  path: '/puzzles/sikinia-parliament',
+  theme: 'Puzzles'
 }];
 
 // Featured interactives (3 fixed ones)