values.yaml image.tag defaults to 'latest' for initial deploy.
Pipeline always pushes both <branch>-<random8> and :latest so
ArgoCD can pull the newest image without a chart version bump.
Mirrors company BasePipeline pattern. Static methods determine
what pipeline stages run per branch:
- PR-*: test only
- feature/*: test + build/push + helm bump + git push
- develop/main/release/hotfix: test + build/push only
imageTag() returns branch-appropriate tag format:
release/x.y.z -> x.y.z, others -> <prefix>-<random8>
