Module host_topology 

STELLAR §A AH-track H0 — host topology + capability sensor (decision D23/D24).

The engine must sense then route instead of grabbing one adapter. Today gpu_context:: shared_gpu() requests a single PowerPreference::HighPerformance device — on a discrete + integrated box that silently takes only the discrete GPU and ignores the integrated GPU and all of system RAM. This module enumerates every adapter, classifies the memory topology (discrete vs unified), reads host RAM, and computes the bounded OS floor (D24). The residency planner (H2) and heterogeneous/cluster dispatch (H3/H5) consume this; it makes no routing decision itself and changes no existing behaviour.

Native only — enumerate_adapters is not available on the wasm/WebGPU path.

Structs

AdapterDesc

One enumerated adapter.

HostTopology

The sensed host: adapters, topology, host memory, and the bounded OS floor (D24).

Enums

AdapterClass

Coarse adapter class (maps wgpu::DeviceType).

HostMemoryTopology

Whole-host memory topology: is there a dedicated VRAM pool, or one shared pool?

Functions

probe_host_topology

Probe the host: enumerate all adapters (deduped across backends), classify, size the floor.