feat(ui): drive toolbar use state from selection

Port the retail selected-object availability predicate into Core and project it through the shared interaction owner. The imported hand now follows canonical selection/object notices, keeps weapon and targeted-tool activation on the existing wield/use cursor paths, and ghosts empty or explicitly unusable selections per the connected UX requirement.

Co-authored-by: Codex <codex@openai.com>

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

@@ -7,6 +7,28 @@ public sealed class ItemInteractionPolicyTests
     private const uint Player = 0x50000001u;
     private const uint GroundContainer = 0x70000001u;
 
+    [Fact]
+    public void ToolbarUseEnabled_matchesRetailSelectionPredicate()
+    {
+        Assert.True(ItemInteractionPolicy.IsToolbarUseEnabled(
+            ItemType.MeleeWeapon,
+            combatUse: 1,
+            useability: ItemUseability.No));
+        Assert.True(ItemInteractionPolicy.IsToolbarUseEnabled(
+            ItemType.Armor | ItemType.Clothing,
+            combatUse: 0,
+            useability: ItemUseability.No));
+        Assert.True(ItemInteractionPolicy.IsToolbarUseEnabled(
+            ItemType.Misc,
+            combatUse: 0,
+            useability: 0x00220008u));
+
+        Assert.False(ItemInteractionPolicy.IsToolbarUseEnabled(
+            ItemType.SpellComponents,
+            combatUse: 0,
+            useability: ItemUseability.No));
+    }
+
     [Fact]
     public void DetermineUseResult_looseItemAndComponentPack_matchRetailPickupBranch()
     {