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>

src/AcDream.Core/Items/AetheriaUnlockState.cs

@@ -0,0 +1,33 @@
+using System;
+
+namespace AcDream.Core.Items;
+
+/// <summary>
+/// Player <c>PropertyInt.AetheriaBitfield (322 / 0x142)</c>. Each bit independently
+/// unlocks one paperdoll sigil location after its corresponding retail quest.
+/// </summary>
+/// <remarks>
+/// Retail: <c>gmPaperDollUI::UpdateAetheria @ 0x004A3E50</c>.
+/// ACE: <c>PropertyInt.AetheriaBitfield</c> + <c>AetheriaBitfield</c>.
+/// </remarks>
+[Flags]
+public enum AetheriaUnlockState : uint
+{
+    None   = 0x0,
+    Blue   = 0x1,
+    Yellow = 0x2,
+    Red    = 0x4,
+    All    = Blue | Yellow | Red,
+}
+
+public static class AetheriaUnlocks
+{
+    public const uint PropertyId = 0x142u;
+
+    public static AetheriaUnlockState Read(ClientObject? player)
+    {
+        if (player?.Properties.Ints.TryGetValue(PropertyId, out int value) != true)
+            return AetheriaUnlockState.None;
+        return (AetheriaUnlockState)(uint)value;
+    }
+}