wire method
void
wire()
Wire native ActivityKit callbacks → backend registration and start
observing (push-to-start tokens, push-started activities, diagnostics).
Called at init when liveActivityEnabled.
Implementation
void wire() {
if (_wired) return;
_wired = true;
NexusPlatform.instance.onLiveActivityToken(_onToken);
if (_platform() == 'ios') unawaited(NexusPlatform.instance.liveActivityObservePushToStart(iosActivityType));
}