[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_Test/CMakeLists.txt

@@ -65,6 +65,8 @@ include(GoogleTest)
 gtest_discover_tests(SanityTest)
 
 add_subdirectory(Buffer)
+add_subdirectory(Framebuffer)
+add_subdirectory(Texture)
 add_subdirectory(VertexArray)
 add_subdirectory(Program)
 if (ENABLE_INTEGRATION_TESTS)