feat(emblem): /emblem/favorite accept-only (persistence deferred)

SVSim.EmulatedEntrypoint/Models/Dtos/Requests/Emblem/EmblemFavoriteRequest.cs

@@ -0,0 +1,17 @@
+using MessagePack;
+using System.Text.Json.Serialization;
+
+namespace SVSim.EmulatedEntrypoint.Models.Dtos.Requests.Emblem;
+
+[MessagePackObject]
+public class EmblemFavoriteRequest : BaseRequest
+{
+    // Spec note: ids are STRINGS on the wire, not ints. Same gotcha as /sleeve/favorite and /degree/favorite.
+    [JsonPropertyName("favorite_add")]
+    [Key("favorite_add")]
+    public List<string> FavoriteAdd { get; set; } = new();
+
+    [JsonPropertyName("favorite_remove")]
+    [Key("favorite_remove")]
+    public List<string> FavoriteRemove { get; set; } = new();
+}