The Details island review commands (Approve/Reject/Park/Cancel) invoked the
hub without catching exceptions. After "Merge all" folds the parent out of
WaitingForReview, pressing Approve made the hub throw a HubException, which
escaped the generated AsyncRelayCommand as an unobserved async-void exception
and crashed the app. Wrap the calls in try/catch like the Tasks island does;
the TaskUpdated broadcast reconciles the UI.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>