Refactor: Split useTransactions hook

Splits the `useTransactions` hook into smaller, more manageable files for improved code organization and maintainability. No functional changes are included.

src/utils/storageUtils.ts

@@ -0,0 +1,66 @@
+
+import { Transaction } from '@/components/TransactionCard';
+
+// 트랜잭션 데이터 불러오기
+export const loadTransactionsFromStorage = (): Transaction[] => {
+  const localData = localStorage.getItem('transactions');
+  if (localData) {
+    return JSON.parse(localData) as Transaction[];
+  }
+  return [];
+};
+
+// 기본 샘플 데이터 생성
+export const createSampleTransactions = (selectedMonth: string): Transaction[] => {
+  return [{
+    id: '1',
+    title: '식료품 구매',
+    amount: 25000,
+    date: `${selectedMonth} 25일, 12:30 PM`,
+    category: '식비',
+    type: 'expense'
+  }, {
+    id: '2',
+    title: '주유소',
+    amount: 50000,
+    date: `${selectedMonth} 24일, 3:45 PM`,
+    category: '교통비',
+    type: 'expense'
+  }, {
+    id: '4',
+    title: '생필품 구매',
+    amount: 35000,
+    date: `${selectedMonth} 18일, 6:00 AM`,
+    category: '생활비',
+    type: 'expense'
+  }, {
+    id: '5',
+    title: '월세',
+    amount: 650000,
+    date: `${selectedMonth} 15일, 10:00 AM`,
+    category: '생활비',
+    type: 'expense'
+  }, {
+    id: '6',
+    title: '식당',
+    amount: 15500,
+    date: `${selectedMonth} 12일, 2:15 PM`,
+    category: '식비',
+    type: 'expense'
+  }];
+};
+
+// 트랜잭션 데이터 저장하기
+export const saveTransactionsToStorage = (transactions: Transaction[]): void => {
+  localStorage.setItem('transactions', JSON.stringify(transactions));
+};
+
+// 예산 불러오기
+export const loadBudgetFromStorage = (): number => {
+  const budgetData = localStorage.getItem('budget');
+  if (budgetData) {
+    const parsedBudget = JSON.parse(budgetData);
+    return parsedBudget.total || 1000000;
+  }
+  return 1000000; // 기본 예산
+};