docs(skills): add GPU vendor toolkit interface spec

[kubestellar-hive]

Architecture artifact

Defines the vendor-agnostic GPU toolkit interface that any GPU vendor integration must satisfy before merging into common. This directly addresses the fragmentation risk identified in #963.

Context

A feature request (common#277) asks for AMD Container Toolkit support. If AMD is added by copying the NVIDIA pattern ad-hoc, the result is two independent paths for kargs, CDI, runtime hooks, and Flatpak GL — one per vendor. Each future GPU vendor adds a third path.

What this adds

docs/skills/gpu-toolkit-interface.md — the vendor-agnostic interface that NVIDIA currently implements and AMD must implement before merging:

#	Capability	NVIDIA (reference)	AMD (gap)
1	Kernel args	kargs.d/00-nvidia.toml	documented
2	CDI spec generation	nvidia-cdi-refresh.{service,path}	amd-cdi-refresh.* needed
3	Runtime toolkit	nvidia-container-toolkit-base	amdgpu-ctk base
4	Flatpak GL extension	ublue-nvidia-flatpak-runtime-sync	evaluate for AMD
5	First-boot hook	preset-enabled service	if needed
6	SELinux policy	tracked (non-blocking)	tracked

A PR checklist is included so AMD PR reviewers have a clear gate.

The document also specifies the directory layout convention (system_files/amd/) and the pattern for adding a third vendor (Intel Arc, etc.).

Addresses #963

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Filed by architect agent (ACMM L5)

— hive: agent=architect backend=copilot model=claude-opus-5 copilot=1.0.59

[castrojo]

Thanks — the six-capability interface and the AMD PR gate checklist directly implement the recommendation in #963, and the concept is right. Two blocking issues:

1. CI is red (pre-commit). validate / Run pre-commit fails: docs/skills/gpu-toolkit-interface.md description is 278 chars (max 256). Shorten the front-matter description: to ≤256 chars.

2. The "NVIDIA reference implementation" claims don't match this repo. The doc gates future AMD PRs against the NVIDIA layout, so it must be accurate:

• kargs.d/00-nvidia.toml — does not exist anywhere in the projectbluefin org under that name.
• nvidia-cdi-refresh.{service,path} and 80-nvidia-container-toolkit.preset — not in system_files/nvidia/ here. system_files/nvidia/ in common ships only ublue-nvidia-flatpak-runtime-sync and its .service (no system-preset/ dir at all). The cdi-refresh units and preset live in bluefin-lts (system_files_overrides/nvidia/usr/lib/systemd/system-preset/80-nvidia-container-toolkit.preset) and dakota (elements/bluefin-nvidia/nvidia-container-toolkit-preset.bst).
• The directory-layout diagram showing "CDI refresh service + path" under system_files/nvidia/usr/lib/systemd/system/ is therefore wrong for common.
• Link docs/skills/oem-hardware-hooks.md is a 404 — actual path is docs/skills/oem-hardware-hooks/SKILL.md.

Note docs/skills/nvidia/references/architecture.md makes some of the same claims, so this may have been inherited — but the new spec should describe where the reference implementation actually lives per repo (common vs bluefin build scripts vs bluefin-lts overrides vs dakota .bst elements), not assert files that aren't in the tree.

[castrojo]

Review findings addressed in 0f84e7b (rebased onto latest main, conflict in docs/SKILL.md resolved):

1. Front-matter description trimmed to 240 chars (CI limit is 256) — validate now passes.
2. NVIDIA reference paths corrected: kargs.d/00-nvidia.toml, nvidia-cdi-refresh.service/.path, and 80-nvidia-container-toolkit.preset are now explicitly attributed to the downstream NVIDIA layers of bluefin-lts and dakota — they do not exist in common. Common's system_files/nvidia/ (Flatpak runtime sync service + script only) is documented as-is in the directory layout section, with a note on the cross-repo split.

Also fixed during rebase: category changed to meta (schema only allows ci-ops/test-authoring/meta), skill linked from docs/SKILL.md, and index.json/index.md regenerated (41 skills). just check and pre-commit run --all-files are clean locally; Validate PR is green.