feat: Manage prometheus resources

[tolusha]

What does this PR do?

1. New metrics package (pkg/deploy/metrics/) — a new reconciler that manages Prometheus resources:
   • ServiceMonitor objects for both Che Server (che-host) and DWO (devworkspace-controller)
   • RBAC (Role + RoleBinding) granting the prometheus-k8s service account access to scrape metrics endpoints
   • Adds the openshift.io/cluster-monitoring: "true" label to the operator namespace so OpenShift's built-in monitoring stack discovers the ServiceMonitors

Screenshot/screencast of this PR

N/A

What issues does this PR fix or reference?

https://redhat.atlassian.net/browse/CRW-8629
https://redhat.atlassian.net/browse/CRW-8589
https://redhat.atlassian.net/browse/CRW-8315

How to test this PR?

1. Deploy Eclipse Che, start a workspace
2. Ensure that me collect devworkspace and che-server specific metrics without creating any additional resources
   https://eclipse.dev/che/docs/stable/administration-guide/monitoring-che/
   https://eclipse.dev/che/docs/stable/administration-guide/monitoring-the-dev-workspace-operator/

Common Test Scenarios

• Deploy Eclipse Che
• Start an empty workspace
• Open terminal and build/run an image
• Stop a workspace
• Check operator logs for reconciliation errors or infinite reconciliation loops

PR Checklist

As the author of this Pull Request I made sure that:

• The Eclipse Contributor Agreement is valid
• Code produced is complete
• Code builds without errors
• Tests are covering the bugfix
• The repository devfile is up to date and works
• Relevant user documentation updated
• Relevant contributing documentation updated
• CI/CD changes implemented, documented and communicated

Reviewers

Reviewers, please comment how you tested the PR when approving it.

[openshift-ci]

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[openshift-ci]

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[tolusha]

/retest

[rohanKanojia]

Sorry, I might not have the full context. Why is pods needed?

[tolusha]

I not 100% sure, probably some requirements
https://eclipse.dev/che/docs/stable/administration-guide/monitoring-che/

[tolusha]

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[tolusha]

/che-ai-assistant generate-che-doc

[rohanKanojia]

While testing it I observe that ServiceMonitor for devworkspace gets created but che-host is not getting created.

On installing Eclipse Che based on these changes and creating a DevWorkspace.

1. ServiceMonitor got created:

kubectl get servicemonitor -neclipse-che                                                                                                                                            
NAME           AGE
devworkspace   106s

2. Role/RoleBinding got created:

kubectl get role -neclipse-che | grep prometheus
devworkspace-prometheus                                           2026-05-14T15:39:05Z

kubectl get rolebinding -neclipse-che | grep prometheus
devworkspace-prometheus                                           Role/devworkspace-prometheus                                           2m17s

These get garbage collected when CheCluster gets deleted, confirming ownerReference is working correctly.

How to enable Che equivalent resources? I can confirm metrics is enabled in CheCluster CR:

oc get checluster -o yaml | grep -A2  metrics                                                                                                                          
      metrics:
        enable: true
      pluginRegistry:

[rohanKanojia]

nit, IMHO this does not add much value vs using defaults.GetCheFlavor() directly

[tolusha]

It leads to some issues during running unit tests.
So, everything having defaults.GetCheFlavor() can't be defined in var/const