feat: ILoginBonusService — JST day-bucketed claim + grant + DTO assembly

GrantIfDueAsync advances streak (1..15 cycle), grants the day's reward via
inventory tx, returns wire-shape DailyLoginBonus. IsDue helper for MyPage.

Also fixes GameConfigurationJsonbTests section-count (15→16) which was broken
since Task 3 added the LoginBonus [ConfigSection] but the assertion wasn't updated.

SVSim.EmulatedEntrypoint/Program.cs

@@ -113,6 +113,7 @@ public class Program
         builder.Services.AddScoped<IArenaTwoPickService, ArenaTwoPickService>();
         builder.Services.AddScoped<IMatchContextBuilder, MatchContextBuilder>();
         builder.Services.AddScoped<IStoryService, StoryService>();
+        builder.Services.AddScoped<ILoginBonusService, LoginBonusService>();
         builder.Services.AddScoped<IDeckListBuilder, DeckListBuilder>();
         builder.Services.AddSingleton<IRandom, SystemRandom>();
         builder.Services.AddSingleton<PuzzleMissionEvaluator>();

SVSim.EmulatedEntrypoint/Services/ILoginBonusService.cs

@@ -0,0 +1,22 @@
+using SVSim.Database.Services.Inventory;
+using SVSim.EmulatedEntrypoint.Models.Dtos;
+
+namespace SVSim.EmulatedEntrypoint.Services;
+
+/// <summary>
+/// Daily login bonus controller-facing API. Single entry point: called from
+/// /load/index inside the existing inventory transaction. Returns null when the viewer
+/// has already claimed today's bonus.
+/// </summary>
+public interface ILoginBonusService
+{
+    /// <summary>
+    /// If due, advances <c>tx.Viewer.LoginBonusStreak</c> + <c>LastLoginBonusClaimedAt</c>,
+    /// grants the day's reward via <paramref name="tx"/>, and returns the populated wire
+    /// DTO. If not due, returns null and leaves viewer state untouched.
+    /// </summary>
+    Task<DailyLoginBonus?> GrantIfDueAsync(IInventoryTransaction tx, CancellationToken ct = default);
+
+    /// <summary>Read-only "would GrantIfDueAsync emit a bonus right now?" — for MyPage flag.</summary>
+    bool IsDue(SVSim.Database.Models.Viewer viewer);
+}

SVSim.EmulatedEntrypoint/Services/LoginBonusService.cs

@@ -0,0 +1,68 @@
+using System.Globalization;
+using SVSim.Database.Models;
+using SVSim.Database.Models.Config;
+using SVSim.Database.Services;
+using SVSim.Database.Services.Inventory;
+using SVSim.EmulatedEntrypoint.Models.Dtos;
+
+namespace SVSim.EmulatedEntrypoint.Services;
+
+public class LoginBonusService : ILoginBonusService
+{
+    private readonly IGameConfigService _config;
+    private readonly TimeProvider _time;
+
+    public LoginBonusService(IGameConfigService config, TimeProvider time)
+    {
+        _config = config;
+        _time = time;
+    }
+
+    public bool IsDue(Viewer viewer)
+    {
+        if (viewer.LastLoginBonusClaimedAt is null) return true;
+        var now = _time.GetUtcNow();
+        var lastClaim = new DateTimeOffset(
+            DateTime.SpecifyKind(viewer.LastLoginBonusClaimedAt.Value, DateTimeKind.Utc));
+        return JstPeriod.DayKey(lastClaim) != JstPeriod.DayKey(now);
+    }
+
+    public async Task<DailyLoginBonus?> GrantIfDueAsync(IInventoryTransaction tx, CancellationToken ct = default)
+    {
+        var viewer = tx.Viewer;
+        if (!IsDue(viewer)) return null;
+
+        var cfg = _config.Get<LoginBonusConfig>();
+        if (cfg.Normal.Count == 0) return null; // catalog misconfigured — nothing to grant
+
+        int newStreak = (viewer.LoginBonusStreak % cfg.Normal.Count) + 1;
+        var entry = cfg.Normal[newStreak - 1];
+
+        await tx.GrantAsync(entry.RewardType, entry.RewardDetailId, entry.RewardNumber, ct);
+
+        viewer.LoginBonusStreak = newStreak;
+        viewer.LastLoginBonusClaimedAt = _time.GetUtcNow().UtcDateTime;
+
+        return new DailyLoginBonus
+        {
+            Normal = new LoginBonusCampaign
+            {
+                Name = cfg.Name,
+                CampaignId = cfg.CampaignId.ToString(CultureInfo.InvariantCulture),
+                Img = cfg.Img,
+                NowCount = newStreak,
+                IsNextReward = true,
+                IsOneDayMultiRewards = false,
+                Rewards = cfg.Normal.Select(n => new LoginBonusReward
+                {
+                    EffectId       = n.EffectId.ToString(CultureInfo.InvariantCulture),
+                    RewardType     = ((int)n.RewardType).ToString(CultureInfo.InvariantCulture),
+                    RewardDetailId = n.RewardDetailId.ToString(CultureInfo.InvariantCulture),
+                    RewardNumber   = n.RewardNumber.ToString(CultureInfo.InvariantCulture),
+                }).ToList(),
+            },
+            Total = null,
+            Campaign = new List<LoginBonusCampaign>(),
+        };
+    }
+}