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.go

@@ -496,11 +496,6 @@ type ragQueryRequest struct {
 	Query string `json:"query"`
 }
 
-// ragDeleteRequest is the POST /api/v1/admin/rag/delete body.
-type ragDeleteRequest struct {
-	ID string `json:"id"`
-}
-
 // adminListRag lists the knowledge-base documents and, when ?query= is present,
 // returns the matching hits too. Without a wired RagStore it degrades to an empty
 // list (backward compatible — never a 500).
@@ -555,33 +550,6 @@ func (s *Server) adminSearchRag(w http.ResponseWriter, r *http.Request) {
 	writeJSON(w, http.StatusOK, map[string]any{"query": req.Query, "hits": ragHitsFrom(hits)})
 }
 
-// adminDeleteRag answers the document delete honestly: write operations
-// (upload/chunk/embed/delete) are milestone M10, so it returns a clear 501 rather
-// than a fabricated success. The route is audited as an admin write.
-func (s *Server) adminDeleteRag(w http.ResponseWriter, r *http.Request) {
-	if s.rag == nil {
-		s.auditClaims(r, "rag.delete", "error")
-		writeError(w, &apperr.AppError{Code: "not_implemented", Message: "知识库 RAG 服务未配置（未注入 RagStore）", HTTPCode: http.StatusNotImplemented})
-		return
-	}
-	var req ragDeleteRequest
-	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
-		writeError(w, apperr.Wrap(apperr.ErrBadRequest, "bad_request", "invalid request body"))
-		return
-	}
-	if strings.TrimSpace(req.ID) == "" {
-		writeError(w, apperr.Wrap(apperr.ErrBadRequest, "bad_request", "id is required"))
-		return
-	}
-	if err := s.rag.DeleteDocument(r.Context(), req.ID); err != nil {
-		s.auditClaims(r, "rag.delete", "error")
-		writeError(w, &apperr.AppError{Code: "not_implemented", Message: "知识库写操作（上传/分块/嵌入/删除）由 M10 后端提供", HTTPCode: http.StatusNotImplemented})
-		return
-	}
-	s.auditClaims(r, "rag.delete", "ok")
-	writeJSON(w, http.StatusOK, map[string]any{"id": req.ID})
-}
-
 // ragDocsFrom maps knowledge docs to their admin wire shape.
 func ragDocsFrom(docs []knowledge.Doc) []AdminRagDoc {
 	out := make([]AdminRagDoc, 0, len(docs))