feat(engine/nfd): publish topology as NFD custom resources

[dmitsh]

Add an NFD engine that translates the canonical topology graph into
NodeFeature and NodeFeatureGroup resources.

Publish accelerator, leaf, spine, and core topology attributes, including the
system node name required for NFD to populate group membership. Support node
selection, namespaced NFD installations, stale-resource cleanup, and existing
GPU clique labels.

[greptile-apps]

Greptile Summary

This PR adds an NFD engine that publishes topology through Node Feature Discovery resources. The main changes are:

• New NFD engine implementation and registry wiring.
• NFD NodeFeature and NodeFeatureGroup object generation.
• Helm schema, values, docs, and RBAC support for engine.name=nfd.
• Tests for NFD object creation, cleanup, and RBAC rendering.

Confidence Score: 5/5

This looks safe to merge.

• No blocking issues found in the changed code.
• The NFD RBAC rule now uses the documented engine.name=nfd value path.
• The Helm test covers the expected NFD custom-resource permissions for that value.

Important Files Changed

Filename	Overview
charts/topograph/templates/rbac.yaml	Adds NFD custom-resource permissions when engine.name is nfd.
charts/topograph/tests/rbac_test.yaml	Adds a Helm test for the NFD RBAC rule.
pkg/engines/nfd/objects.go	Builds and applies NFD custom resources for topology data.

_{Reviews (5): Last reviewed commit: "feat(engine/nfd): publish topology as NF..." | Re-trigger Greptile}

[codecov]

Codecov Report

❌ Patch coverage is 69.01840% with 101 lines in your changes missing coverage. Please review.
✅ Project coverage is 72.83%. Comparing base (8468abe) to head (83c9ddf).
⚠️ Report is 18 commits behind head on main.

Files with missing lines	Patch %	Lines
pkg/engines/nfd/engine.go	25.92%	34 Missing and 6 partials ⚠️
pkg/engines/nfd/objects.go	86.72%	16 Missing and 14 partials ⚠️
pkg/engines/nfd/kubernetes.go	0.00%	25 Missing ⚠️
pkg/engines/k8s/labeler.go	71.42%	4 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #402      +/-   ##
==========================================
+ Coverage   72.15%   72.83%   +0.67%     
==========================================
  Files          89       94       +5     
  Lines        5689     6235     +546     
==========================================
+ Hits         4105     4541     +436     
- Misses       1382     1461      +79     
- Partials      202      233      +31     

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[github-actions]

🌿 Preview your docs: https://nvidia-preview-pull-request-402.docs.buildwithfern.com/topograph