feat: 게시판 신고 — 누적 5건 시 블라인드(관리자만 열람)

- report 테이블(회원당 대상별 1회), comment.blocked 컬럼
- POST /board/posts|comments/{id}/report, 본인 글/댓글 신고 불가
- 글: 5건이면 blocked(기존 열람제한 재사용) / 댓글: blocked → 비관리자 본문 숨김
- 삭제·탈퇴 시 신고 정리

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/main/resources/mapper/CommentMapper.xml

@@ -11,11 +11,12 @@
         <result property="authorGooglePicture" column="author_google_picture"/>
         <result property="authorProfileImage" column="author_profile_image"/>
         <result property="content" column="content"/>
+        <result property="blocked" column="blocked"/>
         <result property="createdAt" column="created_at"/>
     </resultMap>
 
     <select id="findByPostId" parameterType="long" resultMap="commentResultMap">
-        SELECT c.id, c.post_id, c.author_id, c.author_name, c.content, c.created_at,
+        SELECT c.id, c.post_id, c.author_id, c.author_name, c.content, c.blocked, c.created_at,
                m.google_picture AS author_google_picture, m.profile_image AS author_profile_image
         FROM comment c
         LEFT JOIN member m ON m.id = c.author_id
@@ -24,13 +25,17 @@
     </select>
 
     <select id="findById" parameterType="long" resultMap="commentResultMap">
-        SELECT c.id, c.post_id, c.author_id, c.author_name, c.content, c.created_at,
+        SELECT c.id, c.post_id, c.author_id, c.author_name, c.content, c.blocked, c.created_at,
                m.google_picture AS author_google_picture, m.profile_image AS author_profile_image
         FROM comment c
         LEFT JOIN member m ON m.id = c.author_id
         WHERE c.id = #{id}
     </select>
 
+    <update id="updateBlocked">
+        UPDATE comment SET blocked = #{blocked} WHERE id = #{id}
+    </update>
+
     <insert id="insert" parameterType="com.sb.web.board.domain.Comment"
             useGeneratedKeys="true" keyProperty="id">
         INSERT INTO comment (post_id, author_id, author_name, content, created_at)