Grafana dashboards are provisioned via sidecar ConfigMaps (label
grafana_dashboard=1), making the API endpoint reject overwrites. The
import script now resolves ${DS_*} variables and deploys via kubectl
ConfigMap updates with automatic Grafana restart. Falls back to API
import when kubectl is unavailable or SKIP_CONFIGMAP=1.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>