feat(albums): soft-delete albums (admin+owner, hidden & irreversible, both app entries)

契约 deleteAlbum（DELETE /albums/{albumId} → 204 幂等）+ status enum 'deleted'：
- 服务端：softDelete（canView 404→canManage 403 防枚举；乐观锁 claim +
  outbox album.updated priority=high + audit album.delete）；列表/详情/更新/
  成员/资产/分类/水印/照片/展示位绑定全部 deleted→404；公开端 cn
  （status!=='active'）与 ov（isAlbumVisibleOv）天然屏蔽；ov 副本经
  album.updated 载荷 status 直投自动下线
- Admin：列表表格操作「删除」+ 详情页头「删除相册」（确认含不可恢复说明）
- App：操作面板「删除相册」（红字、二次确认、成功退回列表并刷新）
- 验证：API 56/56、App 397/397（analyze 0）、admin typecheck/lint/test/build 绿

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

services/api/src/public/public.service.ts

@@ -112,10 +112,18 @@ export class PublicService {
       where: { albumId: album.id, kind: 'banner', state: 'effective' },
       orderBy: [{ createdAt: 'desc' }, { id: 'desc' }],
     });
-    const bannerRow =
+    let bannerRow =
       bannerAssets.find((row) => row.locale === resolved.locale) ??
       bannerAssets.find((row) => row.locale === null) ??
       null;
+    // 宣传图/封面共用（用户决策 2026-09-23）：banner 缺失回退最新 effective
+    // cover 行（传一张即可两用；与 ov 公开侧同语义）。
+    if (bannerRow === null) {
+      bannerRow = await this.prisma.album_assets.findFirst({
+        where: { albumId: album.id, kind: 'cover', state: 'effective' },
+        orderBy: [{ createdAt: 'desc' }, { id: 'desc' }],
+      });
+    }
     const banner =
       bannerRow === null ? null : await this.presign(bannerRow.objectKey);