Refactor expense form and categories

-   Rename "지출 추가" to "지출 입력" in the add expense dialog.
-   Rename "교통비" to "교통" in categories and ensure all 4 icons are displayed on a single line.

src/components/transaction/categoryUtils.ts

@@ -4,10 +4,11 @@ import { EXPENSE_CATEGORIES } from '@/constants/categoryIcons';
 /**
  * 카테고리 매핑 함수 - 이전 카테고리명을 새 카테고리명으로 변환
  */
-export const mapCategoryToNew = (oldCategory: string): "음식" | "쇼핑" | "교통비" | "기타" => {
+export const mapCategoryToNew = (oldCategory: string): "음식" | "쇼핑" | "교통" | "기타" => {
   if (oldCategory === '식비') return '음식';
   if (oldCategory === '생활비') return '쇼핑';
-  if (EXPENSE_CATEGORIES.includes(oldCategory as any)) return oldCategory as "음식" | "쇼핑" | "교통비" | "기타";
+  if (oldCategory === '교통비') return '교통';
+  if (EXPENSE_CATEGORIES.includes(oldCategory as any)) return oldCategory as "음식" | "쇼핑" | "교통" | "기타";
   // 기본값은 '기타'로 설정
   return '기타';
 };