What type of PR is this?

/kind cleanup
/kind feature

What this PR does / why we need it:

Replaces the 6-field Clients struct (Clientset, DynamicClient, GroveClient, CRClient, RestMapper, RestConfig) with a unified K8s struct that embeds controller-runtime client.Client. This eliminates the "which client do I use?" question from e2e test code — every Kubernetes operation goes through a single client with all types registered in one scheme.

Key changes:

• New e2e/k8s/k8s.go — K8s struct embedding client.Client, with RestConfig for raw HTTP and private clientset for GetLogs/WatchPods (capabilities client.Client lacks). Single scheme registers core K8s, Grove CRDs, KAI scheduling, and KAI topology types.
• All managers migrated — PodManager, NodeManager, ResourceManager, WorkloadManager, PodGroupVerifier, DiagCollector, OperatorConfig, TopologyVerifier now accept client.Client or *K8s instead of *Clients.
• SharedClusterManager simplified — 4 redundant client fields removed, single k8s *K8s field, one GetK8s() accessor replaces GetClients()/GetAllClients()/GetCRClient().
• ResourceManager YAML apply simplified — eliminated RestMapper usage, GVR-based scope checks, and namespace branching. client.Client handles GVK-to-GVR mapping and scoping internally.
• Typed access for KAI resources — PodGroupVerifier and TopologyVerifier now use typed client.Client operations instead of DynamicClient + ConvertUnstructuredToTyped.
• WaitAndGetReadyNode standalone function removed — callers use NodeManager.WaitAndGetReady instead.
• e2e/k8s/clients/ package deleted entirely.

Also includes:

• k8s.Getter[T] helper bridging client.Client.Get to waiter.GetFunc[T]
• computeDomainGVR → computeDomainGVK (removes hardcoded Kind strings)
• suite_test.go fix for nil testctx.Logger in auto-mnnvl tests

Which issue(s) this PR fixes:

Fixes #519

Special notes for reviewer:

• client.Client does not support Watch() or GetLogs() — these require the private kubernetes.Clientset kept inside the K8s struct. Only 3 call sites use these (diagnostics log streaming, update tracker pod watching, unsupported_but_enabled log checking).
• The ResourceManager.ScaleCRD signature changed from GroupVersionResource to GroupVersionKind since client.Client works with GVK, not GVR.
• WorkloadManager.WaitForPodClique no longer takes a groveClient parameter — it uses the embedded client from *K8s.
• ConvertUnstructuredToTyped is still used in setup/grove.go (ConvertTypedToUnstructured) so e2e/k8s/conversions.go is kept.

Does this PR introduce a API change?

NONE

Additional documentation e.g., enhancement proposals, usage docs, etc.:

The e2e test framework now uses a single K8s struct for all Kubernetes operations:

  // Create a K8s client
  k8sClient, err := k8s.New(restConfig)

  // Typed operations (Get, List, Create, Update, Delete, Patch)
  k8sClient.Get(ctx, types.NamespacedName{Name: "my-pod", Namespace: "default"}, &pod)
  k8sClient.List(ctx, &podList, client.InNamespace("default"))
  k8sClient.Create(ctx, &pcs)

  // Log streaming and pod watching
  k8sClient.GetLogs(namespace, podName, opts)
  k8sClient.WatchPods(ctx, namespace, opts)

  // Bridge to waiter package
  waiter.FetchByName(name, k8s.Getter[*v1.Node](k8sClient, ""))