feat: add achievement links

ChatTwo/Util/ChunkUtil.cs

@@ -73,6 +73,11 @@ internal static class ChunkUtil {
                         var reader = new BinaryReader(new MemoryStream(rawPayload.Data[4..]));
                         var id = GetInteger(reader);
                         link = new PartyFinderPayload(id);
+                    } else if (rawPayload.Data.Length > 5 && rawPayload.Data[1] == 0x27 && rawPayload.Data[3] == 0x06) {
+                        // achievement payload
+                        var reader = new BinaryReader(new MemoryStream(rawPayload.Data[4..]));
+                        var id = GetInteger(reader);
+                        link = new AchievementPayload(id);
                     } else if (Equals(rawPayload, RawPayload.LinkTerminator)) {
                         link = null;
                     } else if (Equals(rawPayload, PeriodicRecruitmentLink)) {

ChatTwo/Util/Payloads.cs

@@ -19,3 +19,21 @@ internal class PartyFinderPayload : Payload {
         throw new NotImplementedException();
     }
 }
+
+internal class AchievementPayload : Payload {
+    public override PayloadType Type => (PayloadType) 0x51;
+
+    internal uint Id { get; }
+
+    internal AchievementPayload(uint id) {
+        this.Id = id;
+    }
+
+    protected override byte[] EncodeImpl() {
+        throw new NotImplementedException();
+    }
+
+    protected override void DecodeImpl(BinaryReader reader, long endOfStream) {
+        throw new NotImplementedException();
+    }
+}