SnowCat 雪猫底层全源码：NapCat 4.18.28 底座 + SnowLuma 能力移植 + V8 通道适配 9.9.37

26 包 monorepo（TS 全源码）：
- snowcat-core: NT 内核 API 封装 + listener（含 9.9.37 六回调适配）+ Packet 发包
- snowcat-onebot: OneBot v11 全动作 + MCP Streamable HTTP 适配器 + 稳定线
- snowcat-webui-frontend/backend: 雪猫控制台（React+HeroUI）
- snowcat-shell: 单文件 bundle 出口（vite inlineDynamicImports）
- snowcat-native: napi2native / MoeHoo / ffmpeg / pty 运行时
- 56 项 SnowLuma 独门动作移植（qzone 全家桶/群相册/装扮/闪照/收藏）
- 工具件: 解包器/启动器/便携制作器/doctor

GitHub 关联已全量指向 DandanLLab/SnowCatQQ

packages/snowcat-core/packet/message/builder.ts

@@ -0,0 +1,70 @@
+import * as crypto from 'crypto';
+import { PushMsgBody } from '@/snowcat-core/packet/transformer/proto';
+import { NapProtoEncodeStructType } from 'snowcat-protobuf';
+import { PacketMsg, PacketSendMsgElement } from '@/snowcat-core/packet/message/message';
+import { IPacketMsgElement, PacketMsgTextElement } from '@/snowcat-core/packet/message/element';
+import { SendTextElement } from '@/snowcat-core/index';
+
+export class PacketMsgBuilder {
+  protected static failBackText = new PacketMsgTextElement(
+    {
+      textElement: { content: '[该消息类型暂不支持查看]' },
+    } as SendTextElement
+  );
+
+  buildFakeMsg (selfUid: string, element: PacketMsg[]): NapProtoEncodeStructType<typeof PushMsgBody>[] {
+    return element.map((node): NapProtoEncodeStructType<typeof PushMsgBody> => {
+      const avatar = `https://q.qlogo.cn/headimg_dl?dst_uin=${node.senderUin}&spec=0&img_type=jpg`;
+      const msgContent = node.msg.reduceRight((acc: undefined | Uint8Array, msg: IPacketMsgElement<PacketSendMsgElement>) => {
+        return acc ?? msg.buildContent();
+      }, undefined);
+      const msgElement = node.msg.flatMap(msg => msg.buildElement() ?? []);
+      if (!msgContent && !msgElement.length) {
+        msgElement.push(PacketMsgBuilder.failBackText.buildElement());
+      }
+      return {
+        responseHead: {
+          fromUin: node.senderUin,
+          type: 0,
+          sigMap: 0,
+          toUin: 0,
+          fromUid: '',
+          forward: node.groupId
+            ? undefined
+            : {
+              friendName: node.senderName,
+            },
+          toUid: node.groupId ? undefined : selfUid,
+          grp: node.groupId
+            ? {
+              groupUin: node.groupId,
+              memberName: node.senderName,
+              unknown5: 2,
+            }
+            : undefined,
+        },
+        contentHead: {
+          type: node.groupId ? 82 : 9,
+          subType: node.groupId ? undefined : 4,
+          divSeq: node.groupId ? undefined : 4,
+          autoReply: 0,
+          sequence: crypto.randomBytes(4).readUInt32LE(0),
+          timeStamp: +node.time.toString().substring(0, 10),
+          forward: {
+            field1: 0,
+            field2: 0,
+            field3: node.groupId ? 1 : 2,
+            unknownBase64: avatar,
+            avatar,
+          },
+        },
+        body: {
+          richText: {
+            elems: msgElement,
+          },
+          msgContent,
+        },
+      };
+    });
+  }
+}