Refactor BudgetContext file

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

src/contexts/budget/BudgetContext.tsx

@@ -0,0 +1,27 @@
+
+import React, { createContext, useContext, ReactNode } from 'react';
+import { BudgetContextType } from './types';
+import { useBudgetState } from './useBudgetState';
+
+// Context 생성
+const BudgetContext = createContext<BudgetContextType | undefined>(undefined);
+
+// Context Provider 컴포넌트
+export const BudgetProvider: React.FC<{ children: ReactNode }> = ({ children }) => {
+  const budgetState = useBudgetState();
+  
+  return (
+    <BudgetContext.Provider value={budgetState}>
+      {children}
+    </BudgetContext.Provider>
+  );
+};
+
+// Context 사용을 위한 Hook
+export const useBudget = () => {
+  const context = useContext(BudgetContext);
+  if (!context) {
+    throw new Error('useBudget must be used within a BudgetProvider');
+  }
+  return context;
+};