feat(queue): warn when the base branch has uncommitted changes

Queuing (update_task_status, batch_update_task_status) and run_task_now
now surface a non-blocking baseDirty warning (separate modified/untracked
counts) when the list's working dir has uncommitted changes at enqueue
time, since a new worktree forks from the commit tip and silently misses
them. BaseDirtyChecker caches per working dir for a few seconds so a
batch queue over many tasks in one list only shells out to git once. The
UI surfaces the same warning via the footer error strip on queue actions.

src/ClaudeDo.Ui/ViewModels/Islands/TasksIslandViewModel.cs

@@ -860,10 +860,21 @@ public sealed partial class TasksIslandViewModel : ViewModelBase, IDisposable
     public async Task SetStatusOnRowAsync(TaskRowViewModel row, TaskStatus status)
     {
         if (_worker is null) return;
-        try { await _worker.SetTaskStatusAsync(row.Id, status); }
+        try
+        {
+            var baseDirty = await _worker.SetTaskStatusAsync(row.Id, status);
+            ReportBaseDirty(baseDirty);
+        }
         catch { /* offline; broadcast won't fire */ }
     }
 
+    private void ReportBaseDirty(BaseDirtyWarningDto? warning)
+    {
+        if (warning is null) return;
+        ErrorReported?.Invoke(Loc.T(
+            "vm.queue.baseDirtyWarning", warning.ModifiedCount, warning.UntrackedCount));
+    }
+
     [RelayCommand]
     private async Task SendToQueueAsync(TaskRowViewModel? row)
     {
@@ -890,7 +901,11 @@ public sealed partial class TasksIslandViewModel : ViewModelBase, IDisposable
         // Goes through the worker hub (TaskStateService.EnqueueAsync) rather than a raw EF write
         // so the manual/draft-child guards apply here too; the row refreshes from the resulting
         // TaskUpdated broadcast.
-        try { await _worker.SetTaskStatusAsync(row.Id, TaskStatus.Queued); }
+        try
+        {
+            var baseDirty = await _worker.SetTaskStatusAsync(row.Id, TaskStatus.Queued);
+            ReportBaseDirty(baseDirty);
+        }
         catch (Exception ex) { ErrorReported?.Invoke(Loc.T("vm.tasksIsland.sendToQueueFailed", ex.Message)); }
     }