CCL-10201 to main

[sailajapotnuruHO]

What?

Adds a full Helm chart for this service, including deployment, service, ingress, secrets, external secret, network policy, HPA, PDB, and service monitor templates in hof-rds-api
Adds Helm unit tests for key rendering paths, including ExternalSecret behavior in externalsecret_test.yaml and deployment checks in deployment_test.yaml
Adds chart validation and publish workflows in chart-lint-validate.yaml and chart-publish-ecr.yml
Adds/updates image build and promotion flow in build-scan-push.yml for PR, notprod-uat, and prod promotion paths.
Adds Yarn validation workflow in yarn-validate-build-publish.yml and Dependabot config in dependabot.yml

Why?

Enables GitOps-friendly Helm deployments with environment overrides managed in hof-deploy.
Introduces CI guardrails to catch chart/template regressions before merge.
Standardises image and chart publishing to ECR with clearer nonprod-to-prod promotion control.
Preserves PR commit-level image traceability needed for ephemeral ArgoCD environments.

Screenshots (optional)

Check list

• I have reviewed my own pull request for linting issues (e.g. adding new lines)
• I have written tests (if relevant)
• I have created a JIRA number for my branch
• I have created a JIRA number for my commit
• I have followed the chris beams method for my commit https://cbea.ms/git-commit/
  here is an example commit
• Ensure drone builds are green especially tests
• I will squash the commits before merging