fix(ui): unfreeze the operation spinner and attribute rebind churn

Three causes behind the stuck indicator:
- OperationStatus.End did not retire the generation, so tick work posted
  while the dispatcher was blocked drained afterwards and set
  ShowIndicator back to true on a finished operation.
- The startup update check ran in Task.Run; OperationStatus writes its
  observable properties on the calling thread, so the final
  ShowIndicator=false never reached the binding.
- OperationIndicator overwrote its own DataContext from the Status
  property, which re-targeted the call-site binding. It now scopes the
  DataContext to an inner panel and collapses itself when Status is
  null; every call site switched from DataContext= to Status=.

Also gates the footer connection pill in the command body instead of
CanExecute (a disabled command greyed out the ONLINE chip), and extends
OperationTiming: pid per line, 4 MB rollover, fast successes dropped
(failures always kept), and DetailsIsland.BindAsync now carries the
selection trigger via TasksIslandViewModel.SelectFrom.

src/ClaudeDo.Ui/Views/Islands/TasksIslandView.axaml.cs

@@ -131,7 +131,7 @@ public partial class TasksIslandView : UserControl
         if (!e.GetCurrentPoint(button).Properties.IsLeftButtonPressed) return;
 
         // Select now so the details pane updates whether the gesture becomes a click or a drag.
-        if (DataContext is TasksIslandViewModel vm) vm.SelectedTask = row;
+        if (DataContext is TasksIslandViewModel vm) vm.SelectFrom(row, "pointer-press");
 
         // If the click landed on a nested Button (e.g. the done-toggle checkbox or star),
         // don't start a drag — that would capture the pointer and swallow the inner Click.