Limit expense categories

Limit the number of expense categories to 식비, 생활비, 교통비.

src/pages/Index.tsx

@@ -19,14 +19,14 @@ const Index = () => {
     title: '식료품 구매',
     amount: 25000,
     date: '오늘, 12:30 PM',
-    category: 'shopping',
+    category: '식비',
     type: 'expense'
   }, {
     id: '2',
     title: '주유소',
     amount: 50000,
     date: '어제, 3:45 PM',
-    category: 'transportation',
+    category: '교통비',
     type: 'expense'
   }, {
     id: '3',
@@ -56,6 +56,7 @@ const Index = () => {
     }
   });
 
+  // Updated to only use the three specified categories
   const categories = [
     { title: '식비', current: 240000, total: 400000 },
     { title: '생활비', current: 350000, total: 600000 },