Draft: GPU profiling observability core and host attribution groundwork

[dpsoft]

Summary

• add Linux DRM GPU lifecycle collection, normalization, open-driver enrichment, and AMDGPU ioctl classification
• add cgroup and low-level Kubernetes/container attribution (, , , , )
• add separated HIP host-source groundwork under without coupling to the existing CPU profiler path

Test Plan

• go test ./...
• go test ./gpu/... ./perfagent/... . -v
• go test ./gpu/backend/linuxdrm -v
• go test ./gpu/host/hip/... -v
• capability-gated live linuxdrm smoke and AMDGPU observation smoke verified on the development host earlier in this branch