Console plugin: Artifact browser with OCI metadata

[vtz]

Context

Users need to browse build artifacts (firmware binaries, SBOMs, etc.) directly from the console without using the CLI. The Build API already exposes artifact listing and download endpoints.

Depends on: #44 (scaffold), #45 (detail page to host the tab)

Scope

• "Artifacts" tab on the BuildJob detail page
• File list table: name, size, modification time (from ArtifactListResponse)
• Download button per file (proxied through the console plugin backend)
• OCI artifact metadata section:
  • ociArtifactRef — clickable link to the registry
  • ociArtifactDigest — copyable digest
  • Signed badge (green checkmark if ociSigned: true)
• Plugin proxy configuration to route /bob-api/* calls to the Build API service

Plugin Proxy Config

apiVersion: console.openshift.io/v1
kind: ConsolePlugin
metadata:
  name: bob-console-plugin
spec:
  proxy:
    - alias: bob-api
      endpoint:
        type: Service
        service:
          name: bob-api
          namespace: bob-system
          port: 8080
      authorize: true   # forwards user's OAuth token

const response = await consoleFetch(
  `/api/proxy/plugin/bob-console-plugin/bob-api/builds/${name}/artifacts`
);