Remove custom OffsetDateTime mappings in OpenAPI config and ensure timestamps are converted to UTC in ChatLog.

api/src/main/java/com/alttd/chat/objects/chat_log/ChatLog.java

@@ -12,6 +12,7 @@ import java.sql.PreparedStatement;
 import java.sql.SQLException;
 import java.sql.Timestamp;
 import java.time.Instant;
+import java.time.ZoneOffset;
 import java.util.UUID;
 
 @AllArgsConstructor
@@ -49,7 +50,7 @@ public class ChatLog implements BatchInsertable {
         chatMessageDto.setMessage(GsonComponentSerializer.gson().serialize(miniMessage));
         chatMessageDto.setChannel(ChatMessageDto.ChannelEnum.CHAT);
         chatMessageDto.setServer(server);
-        chatMessageDto.setTimestamp(timestamp);
+        chatMessageDto.setTimestamp(timestamp.atOffset(ZoneOffset.UTC));
         chatMessageDto.setUuid(uuid);
         chatMessageDto.setBlocked(blocked);
         return chatMessageDto;