Test run dashboards refresh automatically when a test run finishes

Test run dashboards no longer get stuck on the “processing” spinner after a run finishes on the xcresult-processor node. Completion events are now relayed through Oban to a clustered web node that can reach every subscribed LiveView, and the test-run detail view also re-checks every 5 seconds while it is in the “processing” state, so the page updates on its own even if a push notification is lost. No manual refresh is needed anymore, and the broadcast payload and topic are unchanged for all other subscribers.