Replaces the shared IsBusy/IsMerging flags in WorktreesOverviewModalViewModel and the reset flow in WorktreesSettingsTabViewModel with dedicated OperationStatus instances shown via OperationIndicator, so a running Refresh no longer blocks the Cleanup indicator. ForceRemove gains a CanExecute guard against re-entrancy while it's running, and the reconcile tick's busy guard now checks all four action statuses instead of the old IsBusy||IsMerging pair.