New skyboxrenderer + moved meshrenderer inside engine and out from main to clean that up

Assets/source/Skybox.frag.hlsl

@@ -0,0 +1,26 @@
+#include "RootConstants.hlsl"
+
+float4 main(float3 ViewDir : TEXCOORD0) : SV_Target0
+{
+    float3 dir = normalize(ViewDir);
+    
+    // Simple Procedural Gradient Skybox Colors
+    float3 skyZenithColor = float3(0.05f, 0.15f, 0.45f); // Deep blue top
+    float3 skyHorizonColor = float3(0.4f, 0.6f, 0.9f); // Light blue horizon
+    float3 groundColor = float3(0.1f, 0.1f, 0.15f); // Dark ground
+    
+    float t = dir.z; // -1 to 1 based on vertical alignment
+    
+    float3 finalColor = groundColor;
+    
+    if (t > 0.0f) {
+        // Blend from horizon to zenith
+        finalColor = lerp(skyHorizonColor, skyZenithColor, t);
+    } else {
+        // Ground - quick blend from horizon to ground
+        finalColor = lerp(skyHorizonColor, groundColor, saturate(-t * 2.0f));
+    }
+    
+    // Combine with overall ambient lighting scale
+    return float4(finalColor, 1.0f);
+}