feat(free-battle): add FreeBattleFinishResponseDto

SVSim.EmulatedEntrypoint/Models/Dtos/FreeBattle/FreeBattleFinishResponseDto.cs

@@ -0,0 +1,35 @@
+using System.Text.Json.Serialization;
+using MessagePack;
+
+namespace SVSim.EmulatedEntrypoint.Models.Dtos.FreeBattle;
+
+/// <summary>
+/// Free-battle /finish wire response. Strict subset of the rank-battle variant —
+/// FreeMatchFinishDetail : MatchFinishBase is an empty subclass (no extra fields),
+/// so the rank-only block (rank / after_battle_point / after_master_point /
+/// battle_point / master_point / successive_win_* / promotion / grand_master) is
+/// dropped. See Shadowverse_Code_2026-05-23/FreeMatchFinishDetail.cs and
+/// MatchFinishBase.cs.
+///
+/// Phase-3 stub: echo battle_result, emit zeros for class XP (class_level=1 so the
+/// UI doesn't underflow). Real reward / class-XP / mission math is a separate spec.
+/// </summary>
+[MessagePackObject(keyAsPropertyName: true)]
+public sealed class FreeBattleFinishResponseDto
+{
+    [JsonPropertyName("battle_result")]
+    [Key("battle_result")]
+    public int BattleResult { get; set; }
+
+    [JsonPropertyName("get_class_experience")]
+    [Key("get_class_experience")]
+    public int GetClassExperience { get; set; }
+
+    [JsonPropertyName("class_experience")]
+    [Key("class_experience")]
+    public int ClassExperience { get; set; }
+
+    [JsonPropertyName("class_level")]
+    [Key("class_level")]
+    public int ClassLevel { get; set; } = 1;
+}