refactor(battle-xp): retire ArenaTwoPickConfig.ClassXpPerBattle for shared BattleXpService

- ArenaTwoPickService now delegates class-XP grants to IBattleXpService
  with BattleXpMode.ArenaTwoPick. Inline GrantClassXp/ResolveClassLevel
  helpers deleted.
- ClassXpPerBattle field removed from ArenaTwoPickConfig; TK2 XP now
  configurable via ArenaTwoPickXpPerWin/XpPerLoss overrides or the global
  BattleXpConfig defaults (100/25).
- Updated 5 test files (ArenaTwoPickService callers) for the new
  constructor arg. Added loss-XP assertion to Finish tests.

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

SVSim.Database/Models/Config/ArenaTwoPickConfig.cs

@@ -10,7 +10,6 @@ public class ArenaTwoPickConfig
 {
     public int RewardScheduleId { get; set; } = 1;
     public int ChallengeId { get; set; } = 1;
-    public int ClassXpPerBattle { get; set; } = 100;
     public int SpotPointsPerBattle { get; set; } = 10;
 
     public double LegendaryRate { get; set; } = 0.06;

SVSim.EmulatedEntrypoint/Services/ArenaTwoPickService.cs

@@ -6,6 +6,7 @@ using SVSim.Database.Models;
 using SVSim.Database.Repositories.Globals;
 using SVSim.Database.Repositories.Viewer;
 using SVSim.Database.Services;
+using SVSim.Database.Services.BattleXp;
 using SVSim.Database.Services.Inventory;
 using SVSim.EmulatedEntrypoint.Models.Dtos.Common.ArenaTwoPick;
 using SVSim.EmulatedEntrypoint.Models.Dtos.Responses.ArenaTwoPick;
@@ -20,6 +21,7 @@ public class ArenaTwoPickService : IArenaTwoPickService
     private readonly IGameConfigService _config;
     private readonly IViewerRepository _viewers;
     private readonly IInventoryService _inv;
+    private readonly IBattleXpService _xp;
     private readonly IRandom _rng;
     private readonly SVSimDbContext _db;
 
@@ -30,11 +32,12 @@ public class ArenaTwoPickService : IArenaTwoPickService
         IGameConfigService config,
         IViewerRepository viewers,
         IInventoryService inv,
+        IBattleXpService xp,
         IRandom rng,
         SVSimDbContext db)
     {
         _runs = runs; _rewards = rewards; _pool = pool; _config = config;
-        _viewers = viewers; _inv = inv; _rng = rng; _db = db;
+        _viewers = viewers; _inv = inv; _xp = xp; _rng = rng; _db = db;
     }
 
     public async Task<TopResponseDto> GetTopAsync(long viewerId)
@@ -375,8 +378,7 @@ public class ArenaTwoPickService : IArenaTwoPickService
         var viewer = await LoadViewerForGrantsAsync(viewerId);
         int before = (int)(viewer.Currency?.SpotPoints ?? 0);
 
-        int newClassXp = GrantClassXp(viewer, run.ClassId, aCfg.ClassXpPerBattle);
-        int classLevel = ResolveClassLevel(viewer, run.ClassId);
+        var xp = await _xp.GrantAsync(viewer, run.ClassId, isWin, BattleXpMode.ArenaTwoPick);
 
         viewer.Currency!.SpotPoints += (ulong)aCfg.SpotPointsPerBattle;
         int after = (int)viewer.Currency.SpotPoints;
@@ -385,29 +387,15 @@ public class ArenaTwoPickService : IArenaTwoPickService
         return new BattleFinishResultDto
         {
             BattleResult = isWin ? 1 : 0,
-            GetClassExperience = aCfg.ClassXpPerBattle,
-            ClassExperience = newClassXp,
-            ClassLevel = classLevel,
+            GetClassExperience = xp.GetXp,
+            ClassExperience = xp.TotalXp,
+            ClassLevel = xp.Level,
             BeforeSpotPoint = before,
             AddSpotPoint = aCfg.SpotPointsPerBattle,
             AfterSpotPoint = after,
         };
     }
 
-    private static int GrantClassXp(SVSim.Database.Models.Viewer viewer, int classId, int xp)
-    {
-        var row = viewer.Classes.FirstOrDefault(c => c.Class.Id == classId);
-        if (row is null) return 0;
-        row.Exp += xp;
-        return row.Exp;
-    }
-
-    private static int ResolveClassLevel(SVSim.Database.Models.Viewer viewer, int classId)
-    {
-        var row = viewer.Classes.FirstOrDefault(c => c.Class.Id == classId);
-        return row is null ? 1 : row.Level;
-    }
-
     // --- projection helpers (kept internal so test subclasses could exercise if needed) ---
 
     internal static EntryInfoDto ProjectEntryInfo(ViewerArenaTwoPickRun run, long viewerId) => new()

SVSim.UnitTests/Services/ArenaTwoPickServiceDraftTests.cs

@@ -64,6 +64,7 @@ public class ArenaTwoPickServiceDraftTests
             scope.ServiceProvider.GetRequiredService<IGameConfigService>(),
             scope.ServiceProvider.GetRequiredService<IViewerRepository>(),
             scope.ServiceProvider.GetRequiredService<IInventoryService>(),
+            scope.ServiceProvider.GetRequiredService<SVSim.Database.Services.BattleXp.IBattleXpService>(),
             new SystemRandom(seed: 1),
             db);
 

SVSim.UnitTests/Services/ArenaTwoPickServiceEntryTests.cs

@@ -59,6 +59,7 @@ public class ArenaTwoPickServiceEntryTests
             config,
             scope.ServiceProvider.GetRequiredService<IViewerRepository>(),
             inv,
+            scope.ServiceProvider.GetRequiredService<SVSim.Database.Services.BattleXp.IBattleXpService>(),
             new SystemRandom(seed: 1234),
             db);
 

SVSim.UnitTests/Services/ArenaTwoPickServiceFinishTests.cs

@@ -80,6 +80,7 @@ public class ArenaTwoPickServiceFinishTests
             scope.ServiceProvider.GetRequiredService<IGameConfigService>(),
             scope.ServiceProvider.GetRequiredService<IViewerRepository>(),
             scope.ServiceProvider.GetRequiredService<IInventoryService>(),
+            scope.ServiceProvider.GetRequiredService<SVSim.Database.Services.BattleXp.IBattleXpService>(),
             new SystemRandom(seed: 1),
             db);
 
@@ -136,13 +137,30 @@ public class ArenaTwoPickServiceFinishTests
         var result = await svc.RecordBattleResultAsync(vid, isWin: true);
 
         Assert.That(result.BattleResult, Is.EqualTo(1));
-        Assert.That(result.GetClassExperience, Is.EqualTo(100));
+        Assert.That(result.GetClassExperience, Is.EqualTo(100),
+            "Default BattleXpConfig.XpPerWin");
         Assert.That(result.AddSpotPoint, Is.EqualTo(10));
         var run = await db.ViewerArenaTwoPickRuns.FirstAsync(r => r.ViewerId == vid);
         Assert.That(run.WinCount, Is.EqualTo(2));
         Assert.That(JsonSerializer.Deserialize<List<bool>>(run.ResultListJson)!.Count, Is.EqualTo(2));
     }
 
+    [Test]
+    public async Task RecordBattleResultAsync_loss_grants_loss_xp()
+    {
+        var (db, svc, vid) = await SetupWithRunAsync(winCount: 0, lossCount: 0);
+        await using var _ = db;
+
+        var result = await svc.RecordBattleResultAsync(vid, isWin: false);
+
+        Assert.That(result.BattleResult, Is.EqualTo(0));
+        Assert.That(result.GetClassExperience, Is.EqualTo(25),
+            "Default BattleXpConfig.XpPerLoss");
+        Assert.That(result.ClassExperience, Is.EqualTo(25),
+            "Fresh viewer with Exp=0, +25 loss XP < curve[1]=50 so no level-up.");
+        Assert.That(result.ClassLevel, Is.EqualTo(1));
+    }
+
     [Test]
     public async Task RecordBattleResultAsync_increments_loss_without_terminating()
     {

SVSim.UnitTests/Services/ArenaTwoPickServiceTopTests.cs

@@ -82,6 +82,6 @@ public class ArenaTwoPickServiceTopTests
     {
         // GetTopAsync only uses _runs — every other dep can be null! because the test path
         // never touches them.
-        return new ArenaTwoPickService(runRepo, null!, null!, null!, null!, null!, null!, db);
+        return new ArenaTwoPickService(runRepo, null!, null!, null!, null!, null!, null!, null!, db);
     }
 }

SVSim.UnitTests/Services/ArenaTwoPickServiceWeightedRewardsTests.cs

@@ -90,6 +90,7 @@ public class ArenaTwoPickServiceWeightedRewardsTests
             scope.ServiceProvider.GetRequiredService<IGameConfigService>(),
             scope.ServiceProvider.GetRequiredService<IViewerRepository>(),
             scope.ServiceProvider.GetRequiredService<IInventoryService>(),
+            scope.ServiceProvider.GetRequiredService<SVSim.Database.Services.BattleXp.IBattleXpService>(),
             rng,
             db);