[Feat] (MG_Backend/DirectVulkan): native GPU indirect draws + draw parameters

- Enable multiDrawIndirect and shaderDrawParameters device features when
  supported (the latter via VkPhysicalDeviceShaderDrawParametersFeatures on
  Vulkan 1.1+), so DrawIndex/BaseInstance SPIR-V builtins are valid and
  vkCmdDrawIndexedIndirect(Count) may draw more than one command.
- Plain glMultiDrawElementsIndirect no longer requires a GL_PARAMETER_BUFFER
  (it previously drew nothing for the standard Flywheel call); it now issues
  a native vkCmdDrawIndexedIndirect, with a per-command loop fallback when
  the multiDrawIndirect feature is unavailable.
- glDrawElementsIndirect / glDrawArraysIndirect / glMultiDrawArraysIndirect
  read the live GPU buffer via native indirect draws instead of the CPU
  shadow (which cannot see compute-written commands); the CPU path remains
  only for client-memory commands.
- Advertise the same five extensions as DirectGLES for Flywheel's
  capability probe.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

MobileGL/MG_Backend/DirectVulkan/BackendObject_DirectVulkan.cpp

@@ -359,7 +359,9 @@ namespace MobileGL::MG_Backend::DirectVulkan {
                                    E_GL_ARB_multi_draw_indirect, E_GL_ARB_indirect_parameters,
                                    E_GL_EXT_framebuffer_object, E_GL_ARB_depth_texture, E_GL_ARB_buffer_storage,
                                    E_GL_ARB_texture_storage, E_GL_ARB_direct_state_access,
-                                   E_GL_ARB_shader_draw_parameters, E_GL_ARB_gpu_shader_int64, E_GL_KHR_debug},
+                                   E_GL_ARB_shader_draw_parameters, E_GL_ARB_gpu_shader_int64, E_GL_KHR_debug,
+                                   E_GL_ARB_gpu_shader5, E_GL_ARB_multi_bind, E_GL_ARB_shading_language_420pack,
+                                   E_GL_ARB_vertex_attrib_binding, E_GL_ARB_shader_image_size},
                     .IsCompatibilityProfile = false
                 },
             .StaticBackendCapability = {.AllowVSOnlyPrograms = false}} {}