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>

apps/mobile/lib/l10n/app_localizations_en.dart

@@ -987,4 +987,17 @@ class AppLocalizationsEn extends AppLocalizations {
   @override
   String get hidePhotoBody =>
       'Viewers will no longer see this photo. Authorized album managers can publish it again.';
+
+  @override
+  String get deleteAlbum => 'Delete album';
+
+  @override
+  String get deleteAlbumConfirmTitle => 'Delete this album?';
+
+  @override
+  String get deleteAlbumConfirmBody =>
+      'The album becomes invisible immediately and cannot be restored. Data is retained; recovery requires operations.';
+
+  @override
+  String get albumDeleted => 'Album deleted';
 }