[Fix] (MG_Backend/DirectVulkan): support Voxy rendering

Implemented:

- Advertise Voxy-required DirectVulkan extensions without raising the reported OpenGL version.

- Add DirectVulkan compute, indirect draw count, DSA, readback, and buffer state paths needed by Voxy.

Fixed:

- Enable Vulkan shaderInt64 and drawIndirectFirstInstance so Voxy baseInstance-driven LOD draws address the correct section data.

- Fix DirectVulkan synchronization, framebuffer, texture readback, and shader interface handling used by Voxy and Minecraft screenshots.

Tests:

- Add MG_Test coverage for DirectVulkan extension advertising, DSA buffer/texture/framebuffer/vertex-array behavior, persistent mapped readback, and shader/program paths.

MobileGL/MG_State/GLState/RenderState/RenderState.cpp

@@ -360,6 +360,17 @@ namespace MobileGL {
                 return m_parameters.FrontFaceModeSetting;
             }
 
+            void RenderState::SetProvokingVertexMode(ProvokingVertexMode mode) {
+                if (m_parameters.ProvokingVertexModeSetting == mode) return;
+
+                m_parameters.ProvokingVertexModeSetting = mode;
+                ++m_version;
+            }
+
+            ProvokingVertexMode RenderState::GetProvokingVertexMode() const {
+                return m_parameters.ProvokingVertexModeSetting;
+            }
+
             // --------------------- Scissor ---------------------
             void RenderState::SetScissorBox(IntVec4 box) {
                 if (m_parameters.ScissorBox == box) return;