Fix TypeScript errors

- Fix TS2353: Object literal may only specify known properties, and 'paymentMethod' does not exist in type 'Transaction'.
- Fix TS1205: Re-exporting a type when 'isolatedModules' is enabled requires using 'export type'.
- Fix TS2741: Property 'getPaymentMethodStats' is missing in type '{ transactions: Transaction[]; budgetData: BudgetData; categoryBudgets: Record<string, number>; selectedTab: BudgetPeriod; setSelectedTab: React.Dispatch<...>; ... 5 more ...; resetBudgetData: () => void; }' but required in type 'BudgetContextType'.

src/contexts/budget/useBudgetState.ts

@@ -40,6 +40,40 @@ export const useBudgetState = () => {
   const getCategorySpending = useCallback(() => {
     return calculateCategorySpending(transactions, categoryBudgets);
   }, [transactions, categoryBudgets]);
+  
+  // 결제 방법 통계 계산 함수 추가
+  const getPaymentMethodStats = useCallback(() => {
+    // 지출 트랜잭션 필터링
+    const expenseTransactions = transactions.filter(t => t.type === 'expense');
+    
+    // 총 지출 계산
+    const totalExpense = expenseTransactions.reduce((acc, curr) => acc + curr.amount, 0);
+    
+    // 결제 방법별 금액 계산
+    const cardExpense = expenseTransactions
+      .filter(t => t.paymentMethod === '신용카드' || !t.paymentMethod) // paymentMethod가 없으면 신용카드로 간주
+      .reduce((acc, curr) => acc + curr.amount, 0);
+      
+    const cashExpense = expenseTransactions
+      .filter(t => t.paymentMethod === '현금')
+      .reduce((acc, curr) => acc + curr.amount, 0);
+    
+    // 결과 배열 생성 - 금액이 큰 순서대로 정렬
+    const result = [
+      { 
+        method: '신용카드', 
+        amount: cardExpense,
+        percentage: totalExpense > 0 ? (cardExpense / totalExpense) * 100 : 0
+      },
+      { 
+        method: '현금', 
+        amount: cashExpense,
+        percentage: totalExpense > 0 ? (cashExpense / totalExpense) * 100 : 0
+      }
+    ].sort((a, b) => b.amount - a.amount);
+    
+    return result;
+  }, [transactions]);
 
   // 예산 목표 업데이트 함수 (기존 함수 래핑)
   const handleBudgetUpdate = useCallback((
@@ -126,6 +160,7 @@ export const useBudgetState = () => {
     
     // 도우미 함수
     getCategorySpending,
+    getPaymentMethodStats, // 여기에 추가
     
     // 데이터 초기화
     resetBudgetData: resetAllData