Refactor BudgetContext file

Refactor BudgetContext.tsx into smaller components and hooks to improve code readability and maintainability.

src/contexts/budget/storageUtils.ts

@@ -0,0 +1,45 @@
+
+import { BudgetData, Transaction } from './types';
+import { DEFAULT_CATEGORY_BUDGETS, getInitialBudgetData } from './budgetUtils';
+
+// 로컬 스토리지에서 트랜잭션 불러오기
+export const loadTransactionsFromStorage = (): Transaction[] => {
+  const storedTransactions = localStorage.getItem('transactions');
+  if (storedTransactions) {
+    return JSON.parse(storedTransactions);
+  }
+  return [];
+};
+
+// 트랜잭션 저장
+export const saveTransactionsToStorage = (transactions: Transaction[]): void => {
+  localStorage.setItem('transactions', JSON.stringify(transactions));
+};
+
+// 카테고리 예산 불러오기
+export const loadCategoryBudgetsFromStorage = (): Record<string, number> => {
+  const storedCategoryBudgets = localStorage.getItem('categoryBudgets');
+  if (storedCategoryBudgets) {
+    return JSON.parse(storedCategoryBudgets);
+  }
+  return DEFAULT_CATEGORY_BUDGETS;
+};
+
+// 카테고리 예산 저장
+export const saveCategoryBudgetsToStorage = (categoryBudgets: Record<string, number>): void => {
+  localStorage.setItem('categoryBudgets', JSON.stringify(categoryBudgets));
+};
+
+// 예산 데이터 불러오기
+export const loadBudgetDataFromStorage = (): BudgetData => {
+  const storedBudgetData = localStorage.getItem('budgetData');
+  if (storedBudgetData) {
+    return JSON.parse(storedBudgetData);
+  }
+  return getInitialBudgetData();
+};
+
+// 예산 데이터 저장
+export const saveBudgetDataToStorage = (budgetData: BudgetData): void => {
+  localStorage.setItem('budgetData', JSON.stringify(budgetData));
+};