Skin Fixer: Switch to a passive approach.

Do not load skin.shpk for ourselves as it causes a race condition.
Instead, inspect the materials' ShPk names.

Penumbra/Communication/CreatedCharacterBase.cs

@@ -16,9 +16,6 @@ public sealed class CreatedCharacterBase : EventWrapper<Action<nint, ModCollecti
     {
         /// <seealso cref="PenumbraApi.CreatedCharacterBase"/>
         Api = int.MinValue,
-
-        /// <seealso cref="Interop.Services.SkinFixer.OnCharacterBaseCreated"/>
-        SkinFixer = 0,
     }
 
     public CreatedCharacterBase()

Penumbra/Communication/MtrlShpkLoaded.cs

@@ -0,0 +1,24 @@
+using System;
+using OtterGui.Classes;
+
+namespace Penumbra.Communication;
+
+/// <summary> <list type="number">
+///     <item>Parameter is the material resource handle for which the shader package has been loaded. </item>
+///     <item>Parameter is the associated game object. </item>
+/// </list> </summary>
+public sealed class MtrlShpkLoaded : EventWrapper<Action<nint, nint>, MtrlShpkLoaded.Priority>
+{
+    public enum Priority
+    {
+        /// <seealso cref="Interop.Services.SkinFixer.OnMtrlShpkLoaded"/>
+        SkinFixer = 0,
+    }
+
+    public MtrlShpkLoaded()
+        : base(nameof(MtrlShpkLoaded))
+    { }
+
+    public void Invoke(nint mtrlResourceHandle, nint gameObject)
+        => Invoke(this, mtrlResourceHandle, gameObject);
+}