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.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);