idz: Add idz2 decoders

src/idz/userdb/decoder/saveTopic.ts

@@ -1,9 +1,21 @@
 import { SaveTopicRequest } from "../request/saveTopic";
 
-saveTopic.msgCode = 0x009a;
-saveTopic.msgLen = 0x0010;
+saveTopic1.msgCode = 0x009a;
+saveTopic1.msgLen = 0x0010;
 
-export function saveTopic(buf: Buffer): SaveTopicRequest {
+export function saveTopic1(buf: Buffer): SaveTopicRequest {
+  const aimeId = buf.readUInt32LE(0x0004);
+
+  return {
+    type: "save_topic_req",
+    aimeId: aimeId !== 0xffffffff ? aimeId : undefined,
+  };
+}
+
+saveTopic2.msgCode = 0x0091;
+saveTopic2.msgLen = 0x0010;
+
+export function saveTopic2(buf: Buffer): SaveTopicRequest {
   const aimeId = buf.readUInt32LE(0x0004);
 
   return {