Fix: Handle undefined budget data

The `useBudgetTabContent` hook was throwing an error when `data` prop was undefined. This commit adds a check to ensure that `data` is defined before accessing its properties.

src/hooks/budget/useBudgetTabContent.ts

@@ -37,15 +37,18 @@ export const useBudgetTabContent = ({
   calculatePercentage,
   onSaveBudget
 }: UseBudgetTabContentProps): UseBudgetTabContentReturn => {
+  // 데이터가 undefined인 경우를 방지하기 위한 기본값 설정
+  const safeData = data || { targetAmount: 0, spentAmount: 0, remainingAmount: 0 };
+  
   const [categoryBudgets, setCategoryBudgets] = useState<Record<string, number>>({});
   const [showBudgetInput, setShowBudgetInput] = useState(false);
-  const spentAmount = data.spentAmount;
-  const targetAmount = data.targetAmount;
+  const spentAmount = safeData.spentAmount;
+  const targetAmount = safeData.targetAmount;
 
   // 로그 추가 - 받은 데이터 확인
   useEffect(() => {
-    console.log(`BudgetTabContent 수신 데이터:`, data);
-  }, [data]);
+    console.log(`BudgetTabContent 수신 데이터:`, safeData);
+  }, [safeData]);
 
   // 전역 예산 데이터가 변경되었을 때 로컬 상태 갱신
   useEffect(() => {