feat: add RenderDoc integration for D3D12 frame capture

- Add mvs/RenderDoc project with sphere rendering + RenderDoc capture
- Dynamic loading of renderdoc.dll without header dependencies
- Auto-capture frames 5-6 to .rdc file
- Copy sphere test resources (shaders, textures) via CMake

MVS/RenderDoc/Res/Shader/sphere.hlsl

@@ -0,0 +1,32 @@
+struct Vertex {
+    float4 pos : POSITION;
+    float4 texcoord : TEXCOORD0;
+};
+
+struct VSOut {
+    float4 pos : SV_POSITION;
+    float4 texcoord : TEXCOORD0;
+};
+
+Texture2D gDiffuseTexture : register(t0);
+SamplerState gSampler : register(s0);
+
+cbuffer MatrixBuffer : register(b0) {
+    float4x4 gProjectionMatrix;
+    float4x4 gViewMatrix;
+    float4x4 gModelMatrix;
+    float4x4 gIT_ModelMatrix;
+};
+
+VSOut MainVS(Vertex v) {
+    VSOut o;
+    float4 positionWS = mul(gModelMatrix, v.pos);
+    float4 positionVS = mul(gViewMatrix, positionWS);
+    o.pos = mul(gProjectionMatrix, positionVS);
+    o.texcoord = v.texcoord;
+    return o;
+}
+
+float4 MainPS(VSOut i) : SV_TARGET {
+    return gDiffuseTexture.Sample(gSampler, float2(i.texcoord.x, i.texcoord.y));
+}