submodule对gitea不管用，所以直接拉了一份拉格兰

Lagrange.Core/Lagrange.OneBot/Utility/Vector2Mapper.cs

@@ -0,0 +1,22 @@
+using System.Numerics;
+using LiteDB;
+
+namespace Lagrange.OneBot.Utility;
+
+public static class Vector2Mapper
+{
+    public static void RegisterType() => BsonMapper.Global.RegisterType(Serialize, Deserialize);
+
+    public static BsonValue Serialize(Vector2 parameter) => new BsonDocument(new Dictionary<string, BsonValue>
+    {
+        { "X", parameter.X },
+        { "Y", parameter.Y }
+    });
+
+    public static Vector2 Deserialize(BsonValue bsonValue)
+    {
+        float x = (float)bsonValue["X"].AsDouble;
+        float y = (float)bsonValue["Y"].AsDouble;
+        return new Vector2(x, y);
+    }
+}