fix(ui): port exact paperdoll body selection

Resolve and sample retail's authored nine-color paperdoll click map, preserve local click coordinates, and select the stable highest-priority worn item with the player fallback. Keep targeted-use body clicks routed to self and pin both synthetic and live-DAT conformance.

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

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

@@ -0,0 +1,113 @@
+using AcDream.Core.Items;
+
+namespace AcDream.Core.Tests.Items;
+
+public sealed class PaperdollSelectionPolicyTests
+{
+    private const uint Player = 0x50000001u;
+
+    [Fact]
+    public void UncoveredValidBodyPart_returnsPlayer()
+    {
+        var objects = TableWithPlayer();
+
+        uint selected = PaperdollSelectionPolicy.GetUpperInventoryObject(
+            objects,
+            Player,
+            EquipMask.HeadWear);
+
+        Assert.Equal(Player, selected);
+    }
+
+    [Fact]
+    public void DefaultPriorityArmor_beatsClothingOnSameBodyPart()
+    {
+        var objects = TableWithPlayer();
+        AddEquipped(objects, 0x50001001u, EquipMask.ChestWear, priority: 20u);
+        AddEquipped(objects, 0x50001002u, EquipMask.ChestArmor, priority: 0u);
+
+        uint selected = PaperdollSelectionPolicy.GetUpperInventoryObject(
+            objects,
+            Player,
+            EquipMask.ChestWear | EquipMask.ChestArmor);
+
+        Assert.Equal(0x50001002u, selected);
+    }
+
+    [Fact]
+    public void HigherExplicitPriorityWins_andTiesPreserveListOrder()
+    {
+        var objects = TableWithPlayer();
+        AddEquipped(objects, 0x50001001u, EquipMask.HeadWear, priority: 12u);
+        AddEquipped(objects, 0x50001002u, EquipMask.HeadWear, priority: 12u);
+        AddEquipped(objects, 0x50001003u, EquipMask.HeadWear, priority: 13u);
+
+        uint selected = PaperdollSelectionPolicy.GetUpperInventoryObject(
+            objects,
+            Player,
+            EquipMask.HeadWear);
+
+        Assert.Equal(0x50001003u, selected);
+
+        objects.Remove(0x50001003u);
+        selected = PaperdollSelectionPolicy.GetUpperInventoryObject(
+            objects,
+            Player,
+            EquipMask.HeadWear);
+        Assert.Equal(0x50001001u, selected);
+    }
+
+    [Fact]
+    public void DefaultArmorPriority_usesCoveredIntersectionRangeExactly()
+    {
+        var objects = TableWithPlayer();
+        AddEquipped(objects, 0x50001001u, EquipMask.LowerLegWear, priority: 1u);
+        AddEquipped(
+            objects,
+            0x50001002u,
+            EquipMask.LowerLegWear | EquipMask.LowerLegArmor,
+            priority: 0u);
+
+        uint selected = PaperdollSelectionPolicy.GetUpperInventoryObject(
+            objects,
+            Player,
+            EquipMask.LowerLegWear | EquipMask.LowerLegArmor);
+
+        // Retail compares the covered value 0x4080 to the inclusive
+        // 0x0200..0x4000 normalization range, so this combined placement stays 0.
+        Assert.Equal(0x50001001u, selected);
+    }
+
+    [Fact]
+    public void InvalidBodyMask_returnsZero()
+    {
+        var objects = TableWithPlayer();
+
+        Assert.Equal(0u, PaperdollSelectionPolicy.GetUpperInventoryObject(
+            objects,
+            Player,
+            EquipMask.None));
+    }
+
+    private static ClientObjectTable TableWithPlayer()
+    {
+        var objects = new ClientObjectTable();
+        objects.AddOrUpdate(new ClientObject { ObjectId = Player, Type = ItemType.Creature });
+        return objects;
+    }
+
+    private static void AddEquipped(
+        ClientObjectTable objects,
+        uint objectId,
+        EquipMask location,
+        uint priority)
+    {
+        objects.AddOrUpdate(new ClientObject
+        {
+            ObjectId = objectId,
+            WielderId = Player,
+            CurrentlyEquippedLocation = location,
+            Priority = priority,
+        });
+    }
+}