feat(chart): add external node ha mode

[coffeexcoin]

What changed

Adds an opt-in HA mode for the abstract-node Helm chart. HA mode splits the external node into a singleton core StatefulSet running the stateful components and an API Deployment that can scale from one to many replicas.

The default HA core component set runs core,tree,tree_fetcher,tree_api, so API replicas can proxy tree-backed proof calls to the core pod. Setting ha.treeApi.enabled=false renders the exact core,tree,tree_fetcher core component list. The existing non-HA path remains the default for backwards compatibility.

Impact

Existing chart consumers continue to get the current single StatefulSet behavior unless they set ha.enabled=true.

When HA mode is enabled, the public service selects API replicas for load balancing, while a separate headless core service supports StatefulSet DNS, health, metrics, consensus ports, and tree API routing.

Validation

• helm lint charts/abstract-node --set database.secretName=db-secret
• helm template abstract charts/abstract-node --set database.secretName=db-secret --set ha.enabled=true --set ha.api.replicaCount=3
• Previously verified default rendering, HA rendering with ha.treeApi.enabled=false, and HA rendering with shutdownWrapper.enabled=true.

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PR-Codex overview

This PR focuses on enhancing the high-availability (HA) features of the abstract-node Helm chart, including the addition of HA services, updates to configurations, and improvements in deployment templates.

Detailed summary

• Updated version in Chart.yaml from 0.1.39 to 0.1.40.
• Added HA support in pdb.yaml, service.yaml, and service-core.yaml.
• Introduced new templates for HA core and API services.
• Modified statefulset.yaml to conditionally set names and args based on HA.
• Enhanced deployment-api.yaml with HA configurations.
• Updated values.yaml to include HA settings and parameters.
• Added helper functions in _helpers.tpl for HA component names.
• Adjusted readiness and liveness probes to support HA scenarios.

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