fix(nvca): apply primary-PV selector in model cache cleanup

[mesutoezdil]

TL;DR

The model cache cleanup selector was left empty because the result of
labels.Selector.Add was discarded. An empty selector matches every object, so
idle cleanup listed every PV in the cluster instead of only model-cache primary
PVs. This skewed the model cache backend count metric and made the cleanup loop
scan all PVs each tick. Reassign the Add result so the requirement applies, plus
a regression test.

Issues

Closes #440

Testing

go test ./pkg/storage/... with envtest passes. Added TestPrimaryPVSelector,
which fails before the fix (empty selector matches an empty label set) and passes
after. No QA needed.

Checklist

• I am familiar with the Contributing Guidelines.
• I have signed off my commits for Developer Certificate of Origin (DCO) compliance.
• New or existing tests cover these changes.
• The documentation is up to date with these changes.

Summary by CodeRabbit

• Bug Fixes

  • Corrected persistent volume label selector construction so only volumes with the required primary-volume label are considered during model cache cleanup.
  • Ensures unlabeled volumes are no longer matched incorrectly.

• Tests

  • Added coverage validating selector behavior for both unlabeled volumes and volumes carrying the expected primary-volume label.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

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Plan: Enterprise

Run ID: 9052d21b-44ea-4aa7-80ed-96457875397f

📥 Commits

Reviewing files that changed from the base of the PR and between c9a42d1 and 2647a51.

📒 Files selected for processing (2)

• src/compute-plane-services/nvca/pkg/storage/modelcache_cleanup.go
• src/compute-plane-services/nvca/pkg/storage/modelcache_cleanup_test.go

🚧 Files skipped from review as they are similar to previous changes (1)

• src/compute-plane-services/nvca/pkg/storage/modelcache_cleanup.go

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📝 Walkthrough

Walkthrough

The primary PV selector now retains its label requirement, and a unit test verifies that it rejects unlabeled objects and matches PVs with the primary label.

Changes

Primary PV selector

Layer / File(s)	Summary
Selector construction and matching validation src/compute-plane-services/nvca/pkg/storage/modelcache_cleanup.go, src/compute-plane-services/nvca/pkg/storage/modelcache_cleanup_test.go	primaryPVSel is reassigned after adding the primary PV label requirement, with tests covering matching and non-matching label sets.

Estimated code review effort: 1 (Trivial) | ~5 minutes

Suggested reviewers: balajinvda

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title follows Conventional Commits and accurately describes the bug fix in model cache cleanup.
Linked Issues check	✅ Passed	The PR satisfies #440 by retaining the selector result and adding the required regression test.
Out of Scope Changes check	✅ Passed	The changes stay focused on the selector fix and its test, with no unrelated modifications.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

Warning

There were issues while running some tools. Please review the errors and either fix the tool's configuration or disable the tool if it's a critical failure.

🔧 golangci-lint (2.12.2)

level=error msg="[linters_context] typechecking error: pattern ./...: directory prefix . does not contain main module or its selected dependencies"

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