Changes

ci(lib): add pod annotations helpers for kyverno labels (#4189)

What

Add shared lib helpers to inject CI annotations into pod templates.
Support both declarative (YAML merge) and scripted (podTemplate
annotations list) pipelines.
Why

Provide minimal metadata (job, refs JSON, trigger user) for Kyverno to
derive labels.
Keep pipeline changes minimal while centralizing annotation logic.
Notes

No label logic in Jenkins; Kyverno handles author/org/repo/env parsing.
Safe for both declarative and scripted pipelines.

This PR is part of a paired rollout with pingcap-ci (annotations) +
ee-ops (Kyverno policy); both need to be merged for labels to take
effect.
https://github.com/PingCAP-QE/ee-ops/pull/1836
 (commit: 5ced69f)