fix: enable imageCubeArray feature + transition all 24 shadow layers

Two validation errors fixed:
1. imageCubeArray feature not enabled → added VkPhysicalDeviceImageCubeArrayFeatures
   to device creation chain (pNext: cubeArray → sync2 → dynamicRendering)
2. Shadow layers 18-23 in UNDEFINED layout → transition ALL 24 layers
   (MaxShadowLights * 6) instead of only numShadowLights * 6
   Descriptor references all 24 layers via CubeArray view

src/Engine.Graphics.Vulkan/VulkanContext.cs

@@ -305,10 +305,17 @@ internal sealed unsafe class VulkanContext : IDisposable
             synchronization2 = VkBool32.True,
         };
 
+        var cubeArrayFeatures = new VkPhysicalDeviceImageCubeArrayFeatures
+        {
+            sType = VkStructureType.PhysicalDeviceImageCubeArrayFeatures,
+            pNext = (nint)(&sync2Features),
+            imageCubeArray = VkBool32.True,
+        };
+
         var renderingFeatures = new VkPhysicalDeviceDynamicRenderingFeatures
         {
             sType = VkStructureType.PhysicalDeviceDynamicRenderingFeatures,
-            pNext = (nint)(&sync2Features),
+            pNext = (nint)(&cubeArrayFeatures),
             dynamicRendering = VkBool32.True,
         };
 

src/Engine.Graphics.Vulkan/VulkanEnums.cs

@@ -78,6 +78,7 @@ public enum VkStructureType : int
     BufferMemoryBarrier2 = 1000314001,
     DependencyInfo = 1000314003,
     PhysicalDeviceDynamicRenderingFeatures = 1000044003,
+    PhysicalDeviceImageCubeArrayFeatures = 1000056000,
     PhysicalDeviceSynchronization2Features = 1000314007,
 }
 

src/Engine.Graphics.Vulkan/VulkanRenderer.cs

@@ -308,12 +308,13 @@ public sealed unsafe class VulkanRenderer : IRenderer, Engine.Graphics.IScreensh
 
         // === SHADOW CUBEMAP ARRAY PASSES (numShadowLights × 6 faces) ===
         int totalLayers = numShadowLights * 6;
+        // Always transition ALL layers (24) to avoid UNDEFINED layout errors for unused layers
         TransitionImageLayout(cmd, _shadowMap.ColorImage,
             VkImageLayout.Undefined, VkImageLayout.ColorAttachmentOptimal,
-            0, 0, 0x400, 0x100, (uint)totalLayers);
+            0, 0, 0x400, 0x100, (uint)(VulkanShadowMap.MaxShadowLights * 6));
         TransitionImageLayoutDepth(cmd, _shadowMap.DepthImage,
             VkImageLayout.Undefined, VkImageLayout.DepthStencilAttachmentOptimal,
-            0, 0, 0x100, 0x200, (uint)totalLayers);
+            0, 0, 0x100, 0x200, (uint)(VulkanShadowMap.MaxShadowLights * 6));
 
         for (int lightIdx = 0; lightIdx < numShadowLights; lightIdx++)
         {
@@ -422,7 +423,7 @@ public sealed unsafe class VulkanRenderer : IRenderer, Engine.Graphics.IScreensh
         // Transition shadow color array: ColorAttachmentOptimal → ShaderReadOnlyOptimal
         TransitionImageLayout(cmd, _shadowMap.ColorImage,
             VkImageLayout.ColorAttachmentOptimal, VkImageLayout.ShaderReadOnlyOptimal,
-            0x400, 0x100, 0x8, 0x20, (uint)totalLayers);
+            0x400, 0x100, 0x8, 0x20, (uint)(VulkanShadowMap.MaxShadowLights * 6));
 
         // === MAIN PASS ===
         TransitionImageLayout(cmd, _swapchain.Images[imageIndex],

src/Engine.Graphics.Vulkan/VulkanStructs.cs

@@ -208,6 +208,14 @@ public unsafe struct VkPhysicalDeviceDynamicRenderingFeatures
     public VkBool32 dynamicRendering;
 }
 
+[StructLayout(LayoutKind.Sequential)]
+public unsafe struct VkPhysicalDeviceImageCubeArrayFeatures
+{
+    public VkStructureType sType;
+    public nint pNext;
+    public VkBool32 imageCubeArray;
+}
+
 [StructLayout(LayoutKind.Sequential)]
 public unsafe struct VkPhysicalDeviceSynchronization2Features
 {