feat: add HPA & PodDisruptionBudget support

[pyhp2017]

Closes #192

Summary

When autoscaling/HPA is used together with a GitOps controller (e.g. ArgoCD), the chart and the HPA fight over the replica count because the StatefulSet/Deployment template hardcodes replicas: 1. This PR fixes that and adds HPA + PDB support.

Problem

• The StatefulSet template hardcodes replicas: 1 when replicaCountEnabled is false.
• An HPA scales the workload up, but the GitOps controller (ArgoCD) resets it back to 1 from the rendered manifest, causing an endless reconcile loop.
• No built-in support for a HorizontalPodAutoscaler or PodDisruptionBudget.

Changes

1. feat(verdaccio): add HPA and stop hardcoding replicas when autoscaling

   • New autoscaling block in values.yaml and an hpa.yaml template (autoscaling/v2) targeting either the Deployment or StatefulSet.
   • When autoscaling.enabled: true, the replicas field is omitted from the Deployment/StatefulSet so the HPA owns the replica count (fixes the ArgoCD <-> HPA loop).

2. feat(verdaccio): add optional PodDisruptionBudget

   • New pdb.yaml template (policy/v1) gated on podDisruptionBudget.enabled, with mutually-exclusive minAvailable / maxUnavailable. Defaults to maxUnavailable: 1.

3. refactor(verdaccio): extract workload kind into helper template

   • New reusable verdaccio.workloadKind helper (Deployment vs StatefulSet) used by the HPA scaleTargetRef.

New values

autoscaling:
  enabled: false
  minReplicas: 2
  maxReplicas: 5
  targetCPUUtilizationPercentage: 80
  # targetMemoryUtilizationPercentage: 80
  behavior: {}

podDisruptionBudget:
  enabled: false
  # minAvailable: 1
  maxUnavailable: 1

Testing

• helm lint passes
• Verified template rendering across 8 scenarios:
  • Default (no autoscaling, no PDB) -- replicas: 1 present, no HPA/PDB
  • autoscaling.enabled=true (Deployment) -- no replicas field, HPA targets Deployment
  • autoscaling.enabled=true + type=statefulset -- no replicas field, HPA targets StatefulSet
  • podDisruptionBudget.enabled=true -- PDB with maxUnavailable: 1
  • Both enabled -- PDB + HPA + no replicas field
  • PDB with minAvailable=2 -- PDB renders minAvailable: 2, no maxUnavailable
  • HPA with memory metric + behavior -- both CPU + memory metrics, behavior block present
  • StatefulSet + autoscaling + PDB -- all render correctly

Chart version

Bumped 4.33.1 -> 4.34.0 (new features warrant a minor bump).

Rebased on latest master (appVersion 6.9.2).

[pyhp2017]

@juanpicado can i please have a review on this?

[Copilot]

Pull request overview

Adds first-class autoscaling and disruption-budget support to the Verdaccio Helm chart, and prevents GitOps controllers from continuously resetting replica counts when an HPA is enabled.

Changes:

• Add autoscaling values plus an autoscaling/v2 (or equivalent) HorizontalPodAutoscaler template targeting Deployment/StatefulSet.
• Add podDisruptionBudget values plus a PodDisruptionBudget template.
• Refactor workload kind selection into a helper and omit replicas in workload templates when autoscaling is enabled.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
README.md	Documents new autoscaling.* and podDisruptionBudget.* values.
charts/verdaccio/values.yaml	Adds default config blocks for HPA and PDB.
charts/verdaccio/templates/deployment.yaml	Omits spec.replicas when autoscaling is enabled so HPA owns scaling.
charts/verdaccio/templates/statefulset.yaml	Same as deployment: omit spec.replicas when autoscaling is enabled.
charts/verdaccio/templates/hpa.yaml	Introduces HPA resource targeting the selected workload kind.
charts/verdaccio/templates/pdb.yaml	Introduces optional PDB resource for voluntary disruption protection.
charts/verdaccio/templates/_helpers.tpl	Adds verdaccio.workloadKind helper for HPA target kind.
charts/verdaccio/Chart.yaml	Bumps chart version to 4.34.0.

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[pyhp2017]

@juanpicado i addressed copilot comments