feat(ui): separate OperationStatus per worktree action (refresh/cleanup/reset/force-remove/batch-merge)

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.

src/ClaudeDo.Ui/Views/Modals/SettingsModalView.axaml

@@ -257,7 +257,9 @@
                       <StackPanel Orientation="Horizontal" Spacing="8">
                         <Button Classes="btn" Content="{loc:Tr settings.cancel}" Command="{Binding Worktrees.CancelResetConfirmCommand}"/>
                         <Button Content="{loc:Tr settings.worktrees.removeAll}" Classes="danger"
-                                Command="{Binding Worktrees.ConfirmResetAllCommand}"/>
+                                Command="{Binding Worktrees.ConfirmResetAllCommand}"
+                                IsEnabled="{Binding !Worktrees.ResetStatus.IsRunning}"/>
+                        <ctl:OperationIndicator Status="{Binding Worktrees.ResetStatus}"/>
                       </StackPanel>
                     </StackPanel>
                   </Border>