Interface FocusHandlingPorts

Register window-focus and document-visibility listeners that pause / resume the animation loop as the page goes background and back. Both listeners early-return when FocusHandlingPorts.getRecordingPanel reports an active capture, so offline recording keeps a stable loop.

getRecordingPanel is a live accessor (not a snapshot) so a focus event that fires mid-dispose — after the orchestrator cleared its recordingPanel field but before events.dispose() removes the listener — sees the updated undefined and the optional-chain short-circuits, matching the original this.recordingPanel?.… behaviour.

Routed through the supplied EventGroup so the listeners are cleaned up on dispose.