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

internal/services/gateway/admin_write_personas_users.go

@@ -132,12 +132,18 @@ func (s *Server) adminUpdatePersona(w http.ResponseWriter, r *http.Request) {
 	writeJSON(w, http.StatusOK, personaSummaryOf(p, characterFromRequest(req)))
 }
 
-// adminCreateUser answers honestly: there is no persistent user table yet (the
-// deployment is a single admin account + API keys), so user creation is deferred
-// to M10 rather than fabricated.
+// adminCreateUser answers honestly: there is no persistent user table and no
+// user-authenticated login to back one (the deployment is a single admin
+// account from .env plus runtime API keys; design/11 is single-user first), so
+// user creation would be a row nobody could log in with. It reports the missing
+// store instead of fabricating a user.
 func (s *Server) adminCreateUser(w http.ResponseWriter, r *http.Request) {
 	s.auditClaims(r, "user.create", "error")
-	writeError(w, &apperr.AppError{Code: "not_implemented", Message: "新增用户/角色存储为 M10 提供（当前为单 admin + APIKey 现状）", HTTPCode: http.StatusNotImplemented})
+	writeError(w, &apperr.AppError{
+		Code:     "not_implemented",
+		Message:  "新增用户/角色未实现：无用户表，登录仅用 .env 单 admin（ADMIN_USERNAME/PASSWORD），角色为 owner>admin>viewer 常量；多用户存储与登录接入需先设计（design/11 单用户为主）",
+		HTTPCode: http.StatusNotImplemented,
+	})
 }
 
 // apiKeyIssueRequest is the POST /api/v1/admin/users/apikey body.