Refactor: Simplify BudgetTabContent

Further simplify the BudgetTabContent component.

src/components/BudgetCategoriesSection.tsx

@@ -15,7 +15,7 @@ const BudgetCategoriesSection: React.FC<BudgetCategoriesSectionProps> = ({
   categories
 }) => {
   return <>
-    <h2 className="text-lg font-semibold mb-3 mt-8">지출 그래프</h2>
+    <h2 className="text-base font-semibold mb-3 mt-8">지출 그래프</h2>
     <div className="neuro-card mb-8">
       {categories.map((category, index) => {
         // 예산 초과 여부 확인