Investigate default value for number inputs

The prompt asks to investigate the current default value (0) for number input fields and consider alternative approaches based on other applications.

src/components/BudgetTabContent.tsx

@@ -29,14 +29,16 @@ const BudgetTabContent: React.FC<BudgetTabContentProps> = ({
 }) => {
   const percentage = calculatePercentage(data.spentAmount, data.targetAmount);
   const [isOpen, setIsOpen] = useState(false);
-  const [budgetInput, setBudgetInput] = useState(data.targetAmount.toString());
+  const [budgetInput, setBudgetInput] = useState(data.targetAmount > 0 ? data.targetAmount.toString() : '');
   
   // 저장된 카테고리 예산을 불러옵니다
   const savedCategoryBudgets = localStorage.getItem('categoryBudgets');
+  const defaultCategoryAmount = data.targetAmount > 0 ? Math.round(data.targetAmount / EXPENSE_CATEGORIES.length) : 0;
+  
   const initialCategoryBudgets = savedCategoryBudgets 
     ? JSON.parse(savedCategoryBudgets) 
     : EXPENSE_CATEGORIES.reduce((acc, category) => {
-        acc[category] = Math.round(data.targetAmount / EXPENSE_CATEGORIES.length);
+        acc[category] = defaultCategoryAmount;
         return acc;
       }, {} as Record<string, number>);