feat: introduce group-level access support in central dashboard and KFAM

[adrianAzoitei]

Description

closes: #308
related: kubeflow/community-distribution#2910 (comment)

Example of adding a group contributor:

NOTE: The approach to the AuthorizationPolicy is still up for debate. See istio section in #308.

apiVersion: security.istio.io/v1
kind: AuthorizationPolicy
metadata:
  annotations:
    group: foo
    role: edit
  creationTimestamp: "2026-06-15T11:42:59Z"
  generation: 1
  name: group-foo-clusterrole-edit
  namespace: issue-308-test
  resourceVersion: "475380"
  uid: 9ba0283f-56b9-4ce0-b2b3-5ed1e0352c67
spec:
  rules:
  - from:
    - source:
        principals:
        - cluster.local/ns/istio-system/sa/istio-ingressgateway-service-account
        - cluster.local/ns/kubeflow/sa/ml-pipeline-ui
    when:
    - key: request.auth.claims[groups]
      values:
      - foo

TODO

• extend KFAM to support Group type RoleBindings: reading, adding, deleting
• extend KFAM to add Istio AuthorizationPolicy suitable for group support
• extend dashboard to support managing and displaying group contributors
• extend dashboard to support kubeflow-groups header
• extend dashboard to list all namespaces with suitable RoleBindings based on both kubeflow-userid and kubeflow-groups headers

AI Policy Disclosure

See https://www.kubeflow.org/docs/about/ai_policy/.
claude-sonnet-4.6 was used as a coding assistant, mostly on the frontend - centraldashboard - component. The model did NOT run in agentic mode, every generated snippet of code was reviewed and / or modified by the submitter.

[google-oss-prow]

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