[Bugfix] update-node-ready-logic

[ankrovv]

What this PR does

Updates model-agent node Ready handling in two related ways:

• Persists storageUri and storagePath in each node-scoped model status ConfigMap entry, then ignores stale Ready/Failed entries when the current BaseModel or ClusterBaseModel spec points at a different artifact.
• Adds periodic artifact integrity reconciliation for models that are already marked Ready on the local node. Basic checks validate required local artifacts cheaply; less frequent deep checks validate persisted SHA256 manifests and reuse OCI Object Storage metadata validation where available.

When integrity validation finds a concrete local artifact failure, model-agent updates both the node model-ready label and the node-scoped ConfigMap entry to Failed, allowing BaseModel and ClusterBaseModel status to move the node from nodesReady to nodesFailed.

Why we need it

A model can keep the same BaseModel/ClusterBaseModel name while its storage source or local path changes. Without checking the storage identity, a node can continue advertising Ready for an older artifact and receive workloads for a path that has not been downloaded on that node.

Ready artifacts can also be deleted or corrupted after initial download. The periodic checker closes that gap by validating already-Ready local artifacts and stopping the node from advertising readiness for a bad model copy.

Related to #613.

How to test

Passed locally:

GOCACHE=/private/tmp/ome-go-build-cache go test ./pkg/modelagent ./pkg/ociobjectstore ./cmd/model-agent ./pkg/controller/v1beta1/basemodel
git diff --check origin/main

Also run locally:

GOCACHE=/private/tmp/ome-go-build-cache go test ./...

The full suite did not complete because this local environment is missing /usr/local/kubebuilder/bin/etcd for envtest packages, and the existing pkg/xet test still fails with cache directory is required. The packages touched by this PR passed in the focused test command above.

Checklist

• Tests added/updated
• Docs updated
• Focused model-agent/controller/object-store tests pass locally

[YouNeedCryDear]

@ankrovv This might be hard to review. Could you breakdown the changes into multiple PRs. Also include a high level design doc for the implementation plan?