fix: correct matrix order (proj*view) + Z depth range for Vulkan

- VP matrix order: proj*view (GLSL column-vector convention)
- Z correction in vertex shader: gl_Position.z = (z+w)*0.5 (OpenGL [-1,1] → Vulkan [0,1])
- Depth test temporarily disabled for debugging

src/Engine.Graphics.Vulkan/Shaders/triangle.vert

@@ -17,6 +17,7 @@ layout(row_major, push_constant) uniform PC {
 
 void main() {
     gl_Position = vp * pc.model * vec4(inPosition, 1.0);
+    gl_Position.z = (gl_Position.z + gl_Position.w) * 0.5;
     fragColor = inColor;
     fragNormal = mat3(pc.model) * inNormal;
 }

src/Engine.Graphics.Vulkan/VulkanPipeline.cs

@@ -118,8 +118,8 @@ internal sealed unsafe class VulkanPipeline : IDisposable
             var depthStencilState = new VkPipelineDepthStencilStateCreateInfo
             {
                 sType = VkStructureType.PipelineDepthStencilStateCreateInfo,
-                depthTestEnable = VkBool32.True,
-                depthWriteEnable = VkBool32.True,
+                depthTestEnable = VkBool32.False,
+                depthWriteEnable = VkBool32.False,
                 depthCompareOp = VkCompareOp.Less,
                 depthBoundsTestEnable = VkBool32.False,
                 stencilTestEnable = VkBool32.False,

src/Engine.Graphics.Vulkan/VulkanRenderer.cs

@@ -273,8 +273,8 @@ internal sealed unsafe class VulkanRenderer : IRenderer, Engine.Graphics.IScreen
     {
         var aspect = (float)_swapchain.Extent.Width / (float)_swapchain.Extent.Height;
         var proj = Matrix4x4.CreatePerspectiveFieldOfView(MathF.PI / 4f, aspect, 0.1f, 100f);
-        var view = Matrix4x4.CreateLookAt(new Vector3(0, 0, -3), Vector3.Zero, Vector3.UnitY);
-        return view * proj;
+        var view = Matrix4x4.CreateLookAt(new Vector3(0, 0, 3), Vector3.Zero, Vector3.UnitY);
+        return proj * view;
     }
 
     private static void TransitionImageLayout(VkCommandBuffer cmd, VkImage image,