feat(): add HA Kustomize overlay configuration

[Maximus-08]

Description

Lays the foundation for running a high-availability worker-operator to prevent single-point-of-failure scenarios, aligning with the KubeSlice HA proposal.
This introduces a dedicated HA Kustomize overlay that allows compiling multi-replica configurations without altering the default single-replica setup.

Proposed Changes:

• config/ha/kustomization.yaml: Standard Kustomization base chaining resources and merge patches.
• config/ha/manager_ha_patch.yaml: Strategic merge patch to scale the operator deployment to 2 replicas and adds preferred pod anti-affinity based on the kubernetes.io/hostname topology key to ensure operator pods are scheduled on distinct nodes.
• config/ha/pdb.yaml: Introduces a PodDisruptionBudget for the worker manager requiring minAvailable: 1 to guarantee high availability during cluster maintenance or node drains.

Fixes #

How Has This Been Tested?

Tested locally by building the Kustomize overlay to verify that the strategic merge patches compile successfully and output the correct resources, replicas, and pod anti-affinity constraints.

Test Cases

• Run kustomize build config/ha to verify successful manifest compilation.
• Verify deployment is scaled to 2 replicas with host anti-affinity rules in the compiled manifest.
• Verify the PodDisruptionBudget is correctly rendered and selects the operator deployment.

Checklist:

• The title of the PR states what changed and the related issues number (used for the release note).
• Does this PR requires documentation updates?
• I've updated documentation as required by this PR.
• I have ran go fmt
• I have updated the helm chart as required by this PR.
• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas.
• I have tested it for all user roles.
• I have added all the required unit test cases.
• I have verified the E2E test cases with new code changes.
• I have added all the required E2E test cases.

Does this PR introduce a breaking change?

[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

Adds a high-availability (HA) kustomize overlay for the operator by increasing replica count, spreading pods across nodes, and introducing a PodDisruptionBudget.

Changes:

• Added a PodDisruptionBudget to limit voluntary disruptions.
• Added a Deployment patch to run 2 replicas with pod anti-affinity preferences.
• Added an HA kustomization overlay that composes default manifests plus HA-specific resources/patches.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 4 comments.

File	Description
config/ha/pdb.yaml	Adds a PodDisruptionBudget intended to protect operator pods during disruptions.
config/ha/manager_ha_patch.yaml	Patches the operator Deployment to 2 replicas and adds preferred pod anti-affinity.
config/ha/kustomization.yaml	Defines the HA overlay composition (base + PDB + strategic merge patch).

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