Implemented DLSiteClient.

JSMR.Infrastructure/Integrations/DLSite/Serialization/NumberConverter.cs

@@ -0,0 +1,23 @@
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+namespace JSMR.Infrastructure.Integrations.DLSite.Serialization;
+
+public sealed class NumberConverter : JsonConverter<int>
+{
+    public override int Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
+    {
+        return reader.TokenType switch
+        {
+            JsonTokenType.Number => reader.TryGetInt32(out var i) ? i : 0,
+            JsonTokenType.String => int.TryParse(reader.GetString(), out var j) ? j : 0,
+            JsonTokenType.False => 0,
+            JsonTokenType.True => 1,
+            JsonTokenType.Null => 0,
+            _ => 0
+        };
+    }
+
+    public override void Write(Utf8JsonWriter writer, int value, JsonSerializerOptions options)
+        => writer.WriteNumberValue(value);
+}