Add routing for subtraction game

Add routes for the subtraction game to be accessible at `/themes/games` and `/index`.

src/components/GamesGallery.tsx

@@ -10,6 +10,7 @@ import NimGame from '@/components/NimGame';
 import AssistedNimGame from '@/components/AssistedNimGame';
 import GoldCoinGame from '@/components/GoldCoinGame';
 import GuessingGame from '@/components/GuessingGame';
+import SubtractionGame from '@/components/SubtractionGame';
 
 interface Game {
   id: string;
@@ -20,6 +21,13 @@ interface Game {
 }
 
 const games: Game[] = [
+  {
+    id: 'subtraction-game',
+    title: 'The Subtraction Game',
+    description: 'A strategic two-player game where players take turns removing circles. Click on any of the last k circles to remove it and all circles to its right!',
+    tags: ['strategy', 'two-player', 'logic', 'game-theory', 'subtraction'],
+    component: SubtractionGame
+  },
   {
     id: 'guessing-game',
     title: 'Number Guessing Game',

src/pages/Index.tsx

@@ -7,6 +7,13 @@ import Layout from "@/components/Layout";
 
 // All interactives data
 const allInteractives = [{
+  id: 'subtraction-game',
+  title: 'The Subtraction Game',
+  description: 'A strategic two-player game where players take turns removing circles. Click on any of the last k circles to remove it and all circles to its right!',
+  tags: ['strategy', 'two-player', 'logic', 'subtraction'],
+  path: '/subtraction-game',
+  theme: 'Games'
+}, {
   id: 'guessing-game',
   title: 'Number Guessing Game',
   description: 'Experience different search algorithms through interactive gameplay. Compare random, linear, and binary search strategies!',