Implemented DLSiteClient.

JSMR.Infrastructure/Integrations/DLSite/Models/ProductBonus.cs

@@ -0,0 +1,23 @@
+using JSMR.Infrastructure.Integrations.DLSite.Serialization;
+using System.Text.Json.Serialization;
+
+namespace JSMR.Infrastructure.Integrations.DLSite.Models;
+
+public class ProductBonus
+{
+    [JsonPropertyName("title")]
+    public string? Title { get; set; }
+
+    [JsonPropertyName("description")]
+    public string? Description { get; set; }
+
+    [JsonPropertyName("dist_flg")]
+    public string? DistributionFlag { get; set; }
+
+    [JsonPropertyName("end_date")]
+    [JsonConverter(typeof(NullableDateTimeConverterUsingDateTimeParse))]
+    public DateTime? EndDate { get; set; }
+
+    [JsonPropertyName("end_date_str")]
+    public string? EndDateString { get; set; }
+}