fix: Fix generateStacitParams in [board]/page.tsx

소괄호로 객체를 감싸는 것을 깜빡해서 에러가 발생
generateStaticParams가 제대로 된 배열을 반환하지 않으니
빌드 시 아래 에러 메시지가 뜸

Error: Page "/blog/[board]" is missing "generateStaticParams()"
so it cannot be used with "output: export" config.

app/blog/[board]/page.tsx

@@ -4,9 +4,7 @@ import { Board, getBoards } from '#/lib/menu'
 import { compareDesc } from 'date-fns'
 
 export const generateStaticParams = async () =>
-  getBoards().map((board: Board) => {
-    board: board.id
-  })
+  getBoards().map((board: Board) => ({ board: board.id }))
 
 export const generateMetadata = ({ params }: { params: { board: string } }) => {
   const boardId = decodeURIComponent(params.board)