fix: clear stale pod-name annotation instead of hard error

[noeljackson]

Summary

When the pod tracked by agents.x-k8s.io/pod-name annotation doesn't exist, clear the stale annotation and fall through to pod creation instead of returning a hard error.

Problem

The ensurePodNameAnnotation function (commit 32cddd3) records the backing pod's name on the Sandbox CR. This is used for stable pod tracking across reconciliations. However, when the annotated pod is deleted (warm pool rotation, eviction, image pull failure), reconcilePod returns a hard error:

if podNameAnnotationExists {
    log.Error(err, "Pod not found")
    return nil, fmt.Errorf("pod in annotation get failed: %w", err)
}

The controller never reaches PATH 3 (create pod). The Sandbox is stuck in a reconcile error loop and the warm pool never becomes ready.

Fix

When the annotated pod isn't found, clear the stale annotation and let pod = nil fall through to pod creation:

if podNameAnnotationExists {
    log.Info("Tracked pod not found, clearing stale annotation", "podName", podName)
    patch := client.MergeFrom(sandbox.DeepCopy())
    delete(sandbox.Annotations, sandboxv1alpha1.SandboxPodNameAnnotation)
    if patchErr := r.Patch(ctx, sandbox, patch); patchErr != nil {
        return nil, fmt.Errorf("failed to clear stale pod name annotation: %w", patchErr)
    }
}

The subsequent ensurePodNameAnnotation call after pod creation re-sets the annotation to track the new pod.

Test plan

• TestReconcilePodClearsStaleAnnotation — sandbox with stale annotation pointing to non-existent pod creates a new pod and updates the annotation
• Updated table test to remove the old hard-error expectation
• All existing reconcilePod tests pass (no behavior change for valid annotations)

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[k8s-ci-robot]

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[k8s-ci-robot]

Hi @noeljackson. Thanks for your PR.

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