feat(admin): 신고 관리 화면 — 신고된 글/댓글 목록·블라인드·신고 무시

- /admin/reports 라우트 + 사이드바 메뉴 + 헤더 타이틀
- boardApi.reports()/dismissReport() 추가(기존 block/unblock 재사용)
- 글 보기·블라인드(사유)·해제·신고 무시 액션

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

src/components/layout/AppSidebar.vue

@@ -25,6 +25,7 @@ const icons = {
   board: '<path d="M21 15a2 2 0 0 1-2 2H7l-4 4V5a2 2 0 0 1 2-2h14a2 2 0 0 1 2 2z"/>',
   users: '<path d="M17 21v-2a4 4 0 0 0-4-4H5a4 4 0 0 0-4 4v2"/><circle cx="9" cy="7" r="4"/><path d="M23 21v-2a4 4 0 0 0-3-3.87"/><path d="M16 3.13a4 4 0 0 1 0 7.75"/>',
   sliders: '<line x1="4" y1="21" x2="4" y2="14"/><line x1="4" y1="10" x2="4" y2="3"/><line x1="12" y1="21" x2="12" y2="12"/><line x1="12" y1="8" x2="12" y2="3"/><line x1="20" y1="21" x2="20" y2="16"/><line x1="20" y1="12" x2="20" y2="3"/><line x1="1" y1="14" x2="7" y2="14"/><line x1="9" y1="8" x2="15" y2="8"/><line x1="17" y1="16" x2="23" y2="16"/>',
+  flag: '<path d="M4 15s1-1 4-1 5 2 8 2 4-1 4-1V3s-1 1-4 1-5-2-8-2-4 1-4 1z"/><line x1="4" y1="22" x2="4" y2="15"/>',
 }
 </script>
 
@@ -106,6 +107,10 @@ const icons = {
           <svg class="menu-icon" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" v-html="icons.sliders" />
           <span>기본 분류 설정</span>
         </RouterLink>
+        <RouterLink to="/admin/reports" class="menu-item">
+          <svg class="menu-icon" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" v-html="icons.flag" />
+          <span>신고 관리</span>
+        </RouterLink>
       </template>
     </nav>
   </aside>