Feature Request: Add support for Indirect Draw Calls (sg_draw_indirect)

Hi @floooh,

Is there any plan to support Indirect Draw calls (such as sg_draw_indirect) in sokol_gfx.h for modern backends that support it (Vulkan, WebGPU, Metal, D3D11)?

Having drawIndirect support would be extremely beneficial for GPU-driven pipelines, specifically for GPU Frustum Culling and LOD management. It would allow us to render large numbers of instances directly on the GPU without requiring CPU readbacks or creating CPU bottlenecks.

Thanks for maintaining such an amazing library!