feat(backthink/admin): ③b — rag/delete 真实现 + D1 推送出口钩子(自建优先→个推兜底) + api-reference 补 D2/D3/D5 补丁

- B5: POST /admin/rag/delete 真做(DeleteDocument→DeleteProject 级联删章节+索引清理, owner+审计, 200/404/500, 500降级兜底); users/iot scenarios+rules 诚实501(无用户表/IoT场景规则模型, 消息写明缺什么, 不伪造), 锁住 501+not_implemented
- D1: backthink/push_outlet.go PushExporter{Export}; pushOutlet 自建HTTP(2xx=送达, token仅Authorization头+error脱敏)优先→Getui兜底(未接入, 诚实日志'getui not integrated'+(false,nil)); backthink.Deps.Exporter → pusher.withExporter, Push 在WS/IM后 exportAsync(detached+5s超时, 失败仅日志, 不破坏现有投递, 限流不上报); config PushOutletConfig(PUSH_EXPORTER_* + GETUI_*占位)
- 前端 Rag.tsx/api.ts 删除后 reload + 类型; Docs/api-client v0.31 + api-reference(#23 owner/200-404, §8.4, 端点表PATCH/DELETE messages + pinned + messages?q=)
- 测试(push_outlet/admin_rag_delete/admin_honest501/knowledge store), 后端+前端build全绿+3平台交叉编译
- 刻意: Getui SDK 未接入(无SDK不硬造), 主人自建服务填 PUSH_EXPORTER_URL/TOKEN 即可

frontend/web/src/lib/api.ts

@@ -448,10 +448,10 @@ export function adminSearchRag(
     body: JSON.stringify({ query }),
   });
 }
-/** POST /api/v1/admin/rag/delete — deletes a document. The backend returns a
- *  clear 501 until M10 lands the write path (upload/chunk/embed/delete). */
-export function adminDeleteRag(id: string): Promise<{ id: string }> {
-  return request<{ id: string }>("/admin/rag/delete", {
+/** POST /api/v1/admin/rag/delete — really deletes a document (project entry +
+ *  cascaded chapters). 404 when the id does not exist. */
+export function adminDeleteRag(id: string): Promise<{ id: string; deleted: boolean }> {
+  return request<{ id: string; deleted: boolean }>("/admin/rag/delete", {
     method: "POST",
     body: JSON.stringify({ id }),
   });