submodule对gitea不管用，所以直接拉了一份拉格兰

Lagrange.Core/Lagrange.OneBot/Message/Entity/ForwardSegment.cs

@@ -0,0 +1,29 @@
+using System.Text.Json.Serialization;
+using Lagrange.Core.Message;
+using Lagrange.Core.Message.Entity;
+
+namespace Lagrange.OneBot.Message.Entity;
+
+[Serializable]
+public partial class ForwardSegment(string name)
+{
+    public ForwardSegment() : this("") { }
+
+    [JsonPropertyName("id")] [CQProperty] public string Name { get; set; } = name;
+}
+
+[SegmentSubscriber(typeof(MultiMsgEntity), "forward")]
+public partial class ForwardSegment : SegmentBase
+{
+    public override void Build(MessageBuilder builder, SegmentBase segment)
+    {
+        if (segment is ForwardSegment forward) builder.Add(new MultiMsgEntity(forward.Name));
+    }
+
+    public override SegmentBase FromEntity(MessageChain chain, IMessageEntity entity)
+    {
+        if (entity is not MultiMsgEntity multiMsg) throw new ArgumentException("Invalid entity type.");
+
+        return new ForwardSegment(multiMsg.ResId ?? "");
+    }
+}