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_honest501_test.go

@@ -0,0 +1,36 @@
+package gateway
+
+import (
+	"net/http"
+	"strings"
+	"testing"
+
+	"git.yeij.top/AskaEth/Cyrene_v2/internal/auth"
+)
+
+// TestAdminMissingStoreWritesHonest501 locks the B5 red line for the endpoints
+// whose backing store does not exist yet: they must answer 501 not_implemented
+// with an explanatory message, never a fabricated success. User creation has no
+// user table/login to persist into, and IoT has no scenario/rule model or store.
+func TestAdminMissingStoreWritesHonest501(t *testing.T) {
+	t.Parallel()
+	srv, ts, jwt := buildEnv(t, cfgDefault(), Deps{})
+	_ = srv
+	tok := signAny(t, jwt, "acct", auth.RoleOwner)
+
+	cases := []string{
+		"/api/v1/admin/users",
+		"/api/v1/admin/iot/scenarios",
+		"/api/v1/admin/iot/rules",
+	}
+	for _, path := range cases {
+		resp, body := doReq(t, http.MethodPost, ts.URL+path, map[string]any{"name": "x"}, tok)
+		if resp.StatusCode != http.StatusNotImplemented {
+			t.Fatalf("%s status = %d, want 501 (body=%s)", path, resp.StatusCode, body)
+		}
+		wantErrorShape(t, body)
+		if !strings.Contains(string(body), "not_implemented") {
+			t.Fatalf("%s body = %s, want not_implemented code", path, body)
+		}
+	}
+}