0.4.0: Claim, Models/ DTOs, compile

LeaderboardSession.ClaimAsync sends onClaim. Generated DTOs live under Models/ with nullable wire fields. Remove incomplete duplicate type files.

Models/Reward.cs

@@ -0,0 +1,17 @@
+// Code generated by apigen. DO NOT EDIT.
+using Newtonsoft.Json;
+
+namespace RudderSdk.Core.Models;
+
+public class Reward
+{
+    [JsonProperty("amount")]
+    public long? Amount { get; set; }
+
+    [JsonProperty("currency")]
+    public string? Currency { get; set; }
+
+    [JsonProperty("itemId")]
+    public string? ItemId { get; set; }
+
+}