feat(load): emit daily_login_bonus via ILoginBonusService

Grant runs inside the existing inventory tx so streak-bump and reward
credit commit atomically with cosmetic backfill.

SVSim.EmulatedEntrypoint/Controllers/LoadController.cs

@@ -49,12 +49,14 @@ public class LoadController : SVSimController
     private readonly SVSimDbContext _db;
     private readonly IInventoryService _inv;
     private readonly ICardMasterPayloadProvider _cardMaster;
+    private readonly ILoginBonusService _loginBonus;
 
     public LoadController(IViewerRepository viewerRepository, IGlobalsRepository globalsRepository,
         IGameConfigService config,
         IBattlePassService battlePass, IViewerMissionStateService missionState,
         SVSimDbContext db, IInventoryService inv,
-        ICardMasterPayloadProvider cardMaster)
+        ICardMasterPayloadProvider cardMaster,
+        ILoginBonusService loginBonus)
     {
         _viewerRepository = viewerRepository;
         _globalsRepository = globalsRepository;
@@ -64,6 +66,7 @@ public class LoadController : SVSimController
         _db = db;
         _inv = inv;
         _cardMaster = cardMaster;
+        _loginBonus = loginBonus;
     }
 
     [HttpPost("index")]
@@ -88,6 +91,7 @@ public class LoadController : SVSimController
         // the response payload would be one /load/index behind on newly-granted cosmetics.
         await using var tx = await _inv.BeginAsync(viewer.Id, ct);
         await tx.BackfillCardCosmeticsAsync(ct);
+        DailyLoginBonus? loginBonusDto = await _loginBonus.GrantIfDueAsync(tx, ct);
         await tx.CommitAsync(ct);
 
         // Lazy-materialize mission/achievement state. Idempotent — safe to call every /load/index.
@@ -229,9 +233,7 @@ public class LoadController : SVSimController
             MaintenanceCards = (await _globalsRepository.GetMaintenanceCards())
                 .Select(e => e.Id).ToList(),
             RedEtherOverrides = new List<RedEtherOverride>(),
-            // Optional per spec (load-index.md:247). Populated by ILoginBonusService (Task 6)
-            // when the viewer has an active bonus period.
-            DailyLoginBonus = null,
+            DailyLoginBonus = loginBonusDto,
             UserRankedMatches = new List<UserRankedMatches>(),
             UserRankInfo = RankFormats.Select(f => new UserRankInfo
             {