fix(paperdoll): port quest-gated Aetheria slots

Add the three authored blue, yellow, and red sigil backgrounds and drive their visibility from player PropertyInt.AetheriaBitfield bits 1/2/4 at login and on live updates, matching gmPaperDollUI::UpdateAetheria. Include the sigil equip masks in the shared slot table and narrow AP-108.

Co-Authored-By: Codex <codex@openai.com>

tests/AcDream.Core.Tests/Items/AetheriaUnlockStateTests.cs

@@ -0,0 +1,29 @@
+using AcDream.Core.Items;
+using Xunit;
+
+namespace AcDream.Core.Tests.Items;
+
+public sealed class AetheriaUnlockStateTests
+{
+    [Fact]
+    public void Missing_property_means_all_slots_locked()
+    {
+        var player = new ClientObject { ObjectId = 1 };
+
+        Assert.Equal(AetheriaUnlockState.None, AetheriaUnlocks.Read(player));
+    }
+
+    [Fact]
+    public void Property_322_preserves_the_three_independent_retail_bits()
+    {
+        var player = new ClientObject { ObjectId = 1 };
+        player.Properties.Ints[AetheriaUnlocks.PropertyId] =
+            (int)(AetheriaUnlockState.Blue | AetheriaUnlockState.Red);
+
+        AetheriaUnlockState actual = AetheriaUnlocks.Read(player);
+
+        Assert.True((actual & AetheriaUnlockState.Blue) != 0);
+        Assert.False((actual & AetheriaUnlockState.Yellow) != 0);
+        Assert.True((actual & AetheriaUnlockState.Red) != 0);
+    }
+}