Add PR checks for Helm charts

[a5anka]

Summary

Add GitHub Actions PR checks for Helm charts to validate chart quality and catch errors before merging.

Components

Path: deployments/helm-charts/

Chart	Description
wso2-ai-agent-management-platform	Main platform chart (console, agent-manager-service, PostgreSQL)
wso2-amp-build-extension	Build workflow templates
wso2-amp-observability-extension	OpenSearch, DataPrepper observability stack

Proposed Checks

Check	Command	Description
Lint	helm lint <chart-path>	Validate chart structure and values
Template	helm template <chart-path>	Verify templates render without errors
Schema Validation	helm lint --strict	Strict linting with schema validation
Kubeconform	kubeconform	Validate generated manifests against K8s schemas

Optional Enhancements

• Add values schema validation if values.schema.json exists

References

• Charts location: deployments/helm-charts/
• Release workflow: .github/workflows/release.yml (uses helm dependency update)