feat(stackdriver-exporter-artifact-registry): deploy to gstg
Dedicated stackdriver exporter for the Artifact Registry storage project (gl-ar-storage-bucket-stg), following the stackdriver-exporter-ai-framework pattern. Exports the GCS bucket (storage.googleapis.com/*) and Cloud CDN (loadbalancing.googleapis.com/https) metrics that today reach no Mimir tenant: AR serves downloads via 302 redirects to CDN-fronted signed URLs, so everything past the redirect is currently invisible. Metrics land in the Runway tenant alongside the rest of AR's series (same collector labels as the ai-framework exporter).
Sequencing:
- Depends on config-mgmt!15245, which creates the
sd-exporter-artifact-registryworkload identity and grants itroles/monitoring.vieweron the AR project. Merge that first. - gstg only, per the non-prod-first rule; gprd follows in a separate MR once this shows Synced + Healthy.
Validated per skills/argocd-service: pre-commit green, helm template against chart 4.13.0 renders the expected --google.project-ids, the three metric prefixes, and --monitoring.metrics-ingest-delay.