fix: useMonthlyExpenseDetail API 경로 수정

- /api/v1/ → /api/proxy/ 프록시 경로로 변경
- 당월 예상 지출 상세 모달 404 에러 해결

src/hooks/useCEODashboard.ts

@@ -856,8 +856,8 @@ export function useMonthlyExpenseDetail() {
 
       // 단일 API 엔드포인트 사용 (transaction_type으로 필터링)
       endpoint = transactionType
-        ? `/api/v1/expected-expenses/dashboard-detail?transaction_type=${transactionType}`
-        : '/api/v1/expected-expenses/dashboard-detail';
+        ? `/api/proxy/expected-expenses/dashboard-detail?transaction_type=${transactionType}`
+        : '/api/proxy/expected-expenses/dashboard-detail';
 
       const transformer = (data: unknown) =>
         transformExpectedExpenseDetailResponse(data as ExpectedExpenseDashboardDetailApiResponse, cardId);