feat(rank-battle): RankBattleController shell + DTOs + routing smoke tests

Stands up the controller with all 13 rank-battle URL routes wired via
explicit absolute [HttpPost] attributes (multi-prefix family — can't ride
[Route(\"[controller]\")]). Real DoMatching / AiStart logic arrives in
later tasks; finish + telemetry + force-finish are returnable stubs as
of this task.

DTOs cover the request + response shapes per the spec. Note the
camelCase wire keys on AiBattlePlayerInfo (sleeveId, emblemId, ...) —
the AI battle subsystem uses camelCase, not the project-default
snake_case, per AIBattleStartTask.Parse's literal Keys.Contains lookups.

DoMatchingResponseDto.NodeServerUrl is non-nullable + always-emit (with
[JsonIgnore(Never)]) — matches Phase 2's TK2 fix because the client's
DoMatchingBase parser calls .ToString() without a Keys.Contains guard.

13 routing smoke tests confirm each URL resolves to the controller.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

SVSim.EmulatedEntrypoint/Models/Dtos/RankBattle/RankBattleFinishRequestDto.cs

@@ -0,0 +1,46 @@
+using System.Text.Json.Serialization;
+using MessagePack;
+
+namespace SVSim.EmulatedEntrypoint.Models.Dtos.RankBattle;
+
+/// <summary>
+/// Standard BattleFinishParam shape — see docs/api-spec/common/types.ts.md and
+/// docs/api-spec/endpoints/post-login/rank-battle/finish.md. Future: promote to
+/// a shared common DTO when a second finish endpoint reuses this.
+/// </summary>
+[MessagePackObject(keyAsPropertyName: true)]
+public sealed class RankBattleFinishRequestDto
+{
+    [JsonPropertyName("battle_result")]
+    [Key("battle_result")]
+    public int BattleResult { get; set; }
+
+    [JsonPropertyName("is_retire")]
+    [Key("is_retire")]
+    public int IsRetire { get; set; }
+
+    [JsonPropertyName("recovery_data")]
+    [Key("recovery_data")]
+    public string? RecoveryData { get; set; }
+
+    [JsonPropertyName("class_id")]
+    [Key("class_id")]
+    public int ClassId { get; set; }
+
+    [JsonPropertyName("total_turn")]
+    [Key("total_turn")]
+    public int TotalTurn { get; set; }
+
+    [JsonPropertyName("evolve_count")]
+    [Key("evolve_count")]
+    public int EvolveCount { get; set; }
+
+    [JsonPropertyName("enemy_evolve_count")]
+    [Key("enemy_evolve_count")]
+    public int EnemyEvolveCount { get; set; }
+
+    // RankBattleFinishTask extends BattleFinishParam with SDTRB.
+    [JsonPropertyName("sdtrb")]
+    [Key("sdtrb")]
+    public int Sdtrb { get; set; }
+}