Fix: pass through last seen update in a few missing places

This is hardly useful in the case of signed player chat messages, as these fundamentally cannot be spoofed or modified - however, for any unsigned input (particularly commands without any signed arguments), 'last seen' updates are still required and should be passed through in a consistent state.

proxy/src/main/java/com/velocitypowered/proxy/connection/client/ConnectedPlayer.java

@@ -1112,6 +1112,7 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player,
       ChatBuilderV2 message = getChatBuilderFactory().builder().asPlayer(this).message(input);
       this.chatQueue.queuePacket(chatState -> {
         message.setTimestamp(chatState.lastTimestamp);
+        message.setLastSeenMessages(chatState.createLastSeen());
         return message.toServer();
       });
     } else {

proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/chat/builder/ChatBuilderV2.java

@@ -21,6 +21,7 @@ import com.velocitypowered.api.network.ProtocolVersion;
 import com.velocitypowered.api.proxy.Player;
 import com.velocitypowered.proxy.protocol.MinecraftPacket;
 import com.velocitypowered.proxy.protocol.packet.chat.ChatType;
+import com.velocitypowered.proxy.protocol.packet.chat.LastSeenMessages;
 import java.time.Instant;
 import net.kyori.adventure.identity.Identity;
 import net.kyori.adventure.text.Component;
@@ -36,6 +37,7 @@ public abstract class ChatBuilderV2 {
   protected @Nullable Identity senderIdentity;
   protected Instant timestamp;
   protected ChatType type = ChatType.CHAT;
+  protected @Nullable LastSeenMessages lastSeenMessages;
 
   protected ChatBuilderV2(ProtocolVersion version) {
     this.version = version;
@@ -77,6 +79,11 @@ public abstract class ChatBuilderV2 {
     return this;
   }
 
+  public ChatBuilderV2 setLastSeenMessages(LastSeenMessages lastSeenMessages) {
+    this.lastSeenMessages = lastSeenMessages;
+    return this;
+  }
+
   public abstract MinecraftPacket toClient();
 
   public abstract MinecraftPacket toServer();

proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/chat/session/SessionChatBuilder.java

@@ -41,6 +41,7 @@ public class SessionChatBuilder extends ChatBuilderV2 {
 
   @Override
   public MinecraftPacket toServer() {
+    LastSeenMessages lastSeenMessages = this.lastSeenMessages != null ? this.lastSeenMessages : new LastSeenMessages();
     if (message.startsWith("/")) {
       if (version.noLessThan(ProtocolVersion.MINECRAFT_1_20_5)) {
         UnsignedPlayerCommandPacket command = new UnsignedPlayerCommandPacket();
@@ -52,7 +53,7 @@ public class SessionChatBuilder extends ChatBuilderV2 {
         command.salt = 0L;
         command.timeStamp = timestamp;
         command.argumentSignatures = new SessionPlayerCommandPacket.ArgumentSignatures();
-        command.lastSeenMessages = new LastSeenMessages();
+        command.lastSeenMessages = lastSeenMessages;
         return command;
       }
     } else {
@@ -62,7 +63,7 @@ public class SessionChatBuilder extends ChatBuilderV2 {
       chat.signature = new byte[0];
       chat.timestamp = timestamp;
       chat.salt = 0L;
-      chat.lastSeenMessages = new LastSeenMessages();
+      chat.lastSeenMessages = lastSeenMessages;
       return chat;
     }
   }

proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/chat/session/SessionChatHandler.java

@@ -73,6 +73,7 @@ public class SessionChatHandler implements ChatHandler<SessionPlayerChatPacket>
                 }
                 return this.player.getChatBuilderFactory().builder().message(packet.message)
                     .setTimestamp(packet.timestamp)
+                    .setLastSeenMessages(newLastSeenMessages)
                     .toServer();
               }
               return packet.withLastSeenMessages(newLastSeenMessages);

proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/chat/session/SessionCommandHandler.java

@@ -86,6 +86,7 @@ public class SessionCommandHandler implements CommandHandler<SessionPlayerComman
     return this.player.getChatBuilderFactory()
         .builder()
         .setTimestamp(packet.timeStamp)
+        .setLastSeenMessages(packet.lastSeenMessages)
         .asPlayer(this.player)
         .message("/" + newCommand)
         .toServer();