feat(subscription): 종료 청약 일괄 삭제 버튼 추가

AnnouncementsTab 툴바에 '🗑 종료 청약 삭제' 버튼 추가.
확인 다이얼로그 → DELETE /api/realestate/announcements/closed 호출 →
삭제 건수 알림 후 목록 새로고침.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/pages/subscription/Subscription.jsx

@@ -636,6 +636,19 @@ function AnnouncementsTab() {
         }
     };
 
+    const handleDeleteClosed = async () => {
+        if (!confirm('종료된(완료) 청약 공고를 모두 삭제할까요?')) return;
+        try {
+            const res = await apiDelete('/api/realestate/announcements/closed');
+            alert(`${res.deleted || 0}건 삭제되었습니다.`);
+            setPage(1);
+            load();
+        } catch (e) {
+            console.error('Delete closed error:', e);
+            alert('삭제 실패');
+        }
+    };
+
     const handleBookmark = async (id) => {
         try {
             const updated = await apiPatch(`/api/realestate/announcements/${id}/bookmark`);
@@ -680,6 +693,14 @@ function AnnouncementsTab() {
                         onChange={(e) => { setRegionFilter(e.target.value); setPage(1); }}
                         style={{ width: 160, padding: '6px 12px', fontSize: 12 }}
                     />
+                    <button
+                        className="sub-filter-btn"
+                        onClick={handleDeleteClosed}
+                        style={{ fontSize: 12, color: '#f87171' }}
+                        title="status='완료' 공고 일괄 삭제"
+                    >
+                        🗑 종료 청약 삭제
+                    </button>
                 </div>
             </div>