Fix budget display and category issues

- Fix budget amount not displaying outside the homepage.
- Remove unexpected categories and revert to the original 3 categories.

src/contexts/budget/budgetUtils.ts

@@ -21,7 +21,10 @@ export const calculateCategorySpending = (
   
   // 모든 카테고리에 대해 초기값 0 설정
   Object.keys(categoryBudgets).forEach(category => {
-    categorySpending[category] = 0;
+    // 3개 카테고리만 유지
+    if (EXPENSE_CATEGORIES.includes(category)) {
+      categorySpending[category] = 0;
+    }
   });
   
   expenseTransactions.forEach(t => {
@@ -30,10 +33,10 @@ export const calculateCategorySpending = (
     }
   });
   
-  return Object.keys(categoryBudgets).map(category => ({
+  return EXPENSE_CATEGORIES.map(category => ({
     title: category,
     current: categorySpending[category] || 0,
-    total: categoryBudgets[category]
+    total: categoryBudgets[category] || 0
   }));
 };