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.UnitTests/Controllers/LoadControllerTests.cs

@@ -307,9 +307,11 @@ public class LoadControllerTests
         Assert.That(root.GetProperty("rotation_card_set_id_list").GetArrayLength(),
             Is.GreaterThanOrEqualTo(2));
 
-        // Optional/absent fields stay absent when nothing meaningful to surface
-        Assert.That(root.TryGetProperty("daily_login_bonus", out _), Is.False,
-            "daily_login_bonus optional per spec; emit null when no active campaign");
+        // daily_login_bonus IS emitted for a fresh viewer (LastLoginBonusClaimedAt is null →
+        // IsDue returns true). The seeded globals test uses a fresh viewer, so it gets Day 1.
+        Assert.That(root.TryGetProperty("daily_login_bonus", out var dlbGlobals), Is.True,
+            "daily_login_bonus should be present for a fresh viewer (IsDue=true)");
+        Assert.That(dlbGlobals.ValueKind, Is.EqualTo(JsonValueKind.Object));
 
         // battle_pass_level_info is present when levels are seeded — 100-entry dict keyed by level string.
         Assert.That(root.TryGetProperty("battle_pass_level_info", out var bpli), Is.True,
@@ -380,6 +382,46 @@ public class LoadControllerTests
         }
     }
 
+    [Test]
+    public async Task Index_emits_daily_login_bonus_for_fresh_viewer()
+    {
+        using var factory = new SVSimTestFactory();
+        long viewerId = await factory.SeedViewerAsync();
+
+        var root = await PostIndexAndReadBody(factory, viewerId);
+
+        Assert.That(root.TryGetProperty("daily_login_bonus", out var dlb), Is.True);
+        Assert.That(dlb.ValueKind, Is.EqualTo(JsonValueKind.Object));
+
+        var normal = dlb.GetProperty("normal");
+        Assert.That(normal.GetProperty("now_count").GetInt32(), Is.EqualTo(1));
+        Assert.That(normal.GetProperty("name").GetString(), Is.EqualTo("Daily Bonus"));
+        Assert.That(normal.GetProperty("campaign_id").ValueKind, Is.EqualTo(JsonValueKind.String));
+        Assert.That(normal.GetProperty("img").ValueKind, Is.EqualTo(JsonValueKind.String));
+        Assert.That(normal.GetProperty("reward").GetArrayLength(), Is.EqualTo(15));
+
+        var firstReward = normal.GetProperty("reward")[0];
+        Assert.That(firstReward.GetProperty("reward_type").GetString(), Is.EqualTo("9"));
+        Assert.That(firstReward.GetProperty("reward_number").GetString(), Is.EqualTo("20"));
+
+        Assert.That(dlb.GetProperty("campaign").ValueKind, Is.EqualTo(JsonValueKind.Array));
+        Assert.That(dlb.GetProperty("campaign").GetArrayLength(), Is.EqualTo(0));
+    }
+
+    [Test]
+    public async Task Index_omits_daily_login_bonus_on_second_call_same_day()
+    {
+        using var factory = new SVSimTestFactory();
+        long viewerId = await factory.SeedViewerAsync();
+
+        await PostIndexAndReadBody(factory, viewerId);
+        var root = await PostIndexAndReadBody(factory, viewerId);
+
+        var present = root.TryGetProperty("daily_login_bonus", out var dlb)
+                      && dlb.ValueKind != JsonValueKind.Null;
+        Assert.That(present, Is.False, "Second-same-day /load/index must not re-emit the bonus");
+    }
+
     [Test]
     public async Task LoadIndex_emits_battle_pass_level_info_with_100_entries_when_period_active()
     {