Backport 4c971b4 from #3261.

What does this PR do?

Add a reason to the status since the status update is invalid without it:

{"level":"ERROR","ts":"2026-07-15T13:55:32.274Z","logger":"controllers.DatadogAgent","msg":"unable to update profile status","datadogagentprofile":"datadogagentprofile-sample","datadogagentprofile_namespace":"default","error":"DatadogAgentProfile.datadoghq.com \"datadogagentprofile-sample\" is invalid: status.conditions[1].reason: Invalid value: \"\": conditions[1].reason in body should be at least 1 chars long","stacktrace":"github.com/DataDog/datadog-operator/internal/controller/datadogagent.(*Reconciler).reconcileProfiles\n\t/workspace/internal/controller/datadogagent/profile.go:97\ngithub.com/DataDog/datadog-operator/internal/controller/datadogagent.(*Reconciler).reconcileInstanceV3\n\t/workspace/internal/controller/datadogagent/controller_reconcile_v2.go:118\ngithub.com/DataDog/datadog-operator/internal/controller/datadogagent.(*

Motivation

What inspired you to submit this pull request?

Additional Notes

Anything else we should know when reviewing?

Minimum Agent Versions

Are there minimum versions of the Datadog Agent and/or Cluster Agent required?

• Agent: vX.Y.Z
• Cluster Agent: vX.Y.Z

Describe your test plan

Create an invalid DAP

  config:
    override:
      nodeAgent:
        nodeSelector:
          disktype: ssd

The operator should reject it: {"level":"ERROR","ts":"2026-07-15T14:17:10.961Z","logger":"controllers.DatadogAgent","msg":"unable to reconcile profile","datadogagentprofile":"invalid-dap","datadogagentprofile_namespace":"default","error":"profile spec is invalid: component node selector override is not supported","stacktrace":...}

The dap status should update:

$ kubectl get dap
NAME          VALID   APPLIED   AGE
invalid-dap   False   Unknown   24m

Checklist

• PR has at least one valid label: bug, enhancement, refactoring, documentation, tooling, and/or dependencies
• PR has a milestone or the qa/skip-qa label
• All commits are signed (see: signing commits)