feat(B2): 附件管理改"未使用"语义+用途列;banner/link 上传带 scene

- AttachmentManage: orphanCount→unusedCount(零残留),用途列(文章/轮播/友链/站点配置/未使用)
- BannerManage/LinkManage 上传 action 传 scene;ArticleList 删除提示文案同步
- types AttachmentVo 增 refType;vitest 24/24+build 绿

src/api/module/cms.ts

@@ -166,7 +166,7 @@ class ArticleApi {
 
 class AttachmentApi {
     page(siteId: number, orphanOnly: boolean, page: number, pageSize: number) {
-        return get<PageResult<AttachmentVo> & { orphanCount: number }>(`${ATTACHMENT}/page`, {
+        return get<PageResult<AttachmentVo> & { unusedCount: number }>(`${ATTACHMENT}/page`, {
             siteId,
             orphanOnly,
             page,