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/ViewModels/IslandsShellViewModel.cs

@@ -303,7 +303,7 @@ public sealed partial class IslandsShellViewModel : ViewModelBase, IDisposable
         _git = git;
         Lists.SelectionChanged += (_, _) => Tasks.LoadForList(Lists.SelectedList);
         Lists.SelectionChanged += (_, _) => _ = RefreshStaleWorkerCheckAsync();
-        Tasks.SelectionChanged += (_, _) => Details.Bind(Tasks.SelectedTask);
+        Tasks.SelectionChanged += (_, _) => Details.Bind(Tasks.SelectedTask, Tasks.SelectionSource);
         Tasks.NotesRequested += () => Details.ShowNotes();
         Tasks.PrepRequested += () => Details.ShowPrep();
         Tasks.ErrorReported += FlashFooterError;
@@ -340,7 +340,7 @@ public sealed partial class IslandsShellViewModel : ViewModelBase, IDisposable
                 Lists.LetClaudeHandleListCommand.Execute(row);
         };
         Details.ErrorReported += FlashFooterError;
-        Details.CloseDetail = () => Tasks.SelectedTask = null;
+        Details.CloseDetail = () => Tasks.SelectFrom(null, "close-detail");
         Details.DeleteFromList = row =>
         {
             Tasks.LoadForList(Lists.SelectedList);
@@ -354,7 +354,6 @@ public sealed partial class IslandsShellViewModel : ViewModelBase, IDisposable
                 OnPropertyChanged(nameof(ConnectionText));
                 OnPropertyChanged(nameof(IsOffline));
                 OnPropertyChanged(nameof(CanOpenWorkerConnectionHelp));
-                OpenWorkerConnectionHelpCommand.NotifyCanExecuteChanged();
             }
         };
         Worker.WorkerLogReceivedEvent += OnWorkerLogReceived;
@@ -390,11 +389,16 @@ public sealed partial class IslandsShellViewModel : ViewModelBase, IDisposable
         {
             if (e.PropertyName == nameof(OperationStatus.IsRunning)) CheckForUpdatesCommand.NotifyCanExecuteChanged();
         };
-        // Fire-and-forget startup check — never block UI.
-        _ = Task.Run(async () =>
-        {
-            try { await _updateCheck.CheckNowAsync(CancellationToken.None); } catch { }
-        });
+        // Fire-and-forget startup check — never block UI. Deliberately *not* Task.Run: the check is
+        // pure async I/O (no sync blocking), and `OperationStatus` writes its observable properties
+        // on the calling thread. From a threadpool thread the final `ShowIndicator=false` never
+        // reaches the binding, so the indicator froze on the last tick ("Checking… 00:03").
+        _ = StartupUpdateCheckAsync();
+    }
+
+    private async Task StartupUpdateCheckAsync()
+    {
+        try { await _updateCheck.CheckNowAsync(CancellationToken.None); } catch { }
     }
 
     public void Dispose()
@@ -526,8 +530,12 @@ public sealed partial class IslandsShellViewModel : ViewModelBase, IDisposable
         if (Dialogs is not null) await Dialogs.ShowWorkerConnectionAsync(vm);
     }
 
-    [RelayCommand(CanExecute = nameof(CanOpenWorkerConnectionHelp))]
-    private Task OpenWorkerConnectionHelp() => OpenWorkerConnectionHelpAsync();
+    // The gate lives in the body, not in CanExecute: the footer pill *is* this button, so a
+    // disabled command renders the "ONLINE" chip greyed out — which reads as a broken connection,
+    // the opposite of what it says.
+    [RelayCommand]
+    private Task OpenWorkerConnectionHelp() =>
+        CanOpenWorkerConnectionHelp ? OpenWorkerConnectionHelpAsync() : Task.CompletedTask;
 
     [RelayCommand]
     private async Task OpenRepoImport()