feat(ui): add queueing and scheduling from task row context menu

- Right-click on a task row exposes Send to queue / Remove from queue
  and Schedule for... / Clear schedule actions.
- New virtual:queued list in the sidebar with live count.
- Sidebar counts are now computed (open per list, running, queued,
  review) and refreshed on task- and worker-side events.
- Sending a task to the queue wakes the worker so it starts immediately.

src/ClaudeDo.Ui/Views/Islands/TaskRowView.axaml

@@ -19,11 +19,22 @@
             Margin="0"
             Classes.selected="{Binding IsSelected}"
             Classes.done="{Binding Done}">
-      <Grid ColumnDefinitions="4,32,*,32" Margin="6,8,10,8">
-
-      <!-- Left accent bar (visible when selected) -->
-      <Border Grid.Column="0" Classes="task-row-accent"
-              IsVisible="{Binding IsSelected}"/>
+      <Border.ContextMenu>
+        <ContextMenu>
+          <MenuItem Header="Send to queue"
+                    IsVisible="{Binding !IsQueued}"
+                    Click="OnSendToQueueClick"/>
+          <MenuItem Header="Remove from queue"
+                    IsVisible="{Binding IsQueued}"
+                    Click="OnRemoveFromQueueClick"/>
+          <Separator/>
+          <MenuItem Header="Schedule for..." Click="OnScheduleForClick"/>
+          <MenuItem Header="Clear schedule"
+                    IsVisible="{Binding HasSchedule}"
+                    Click="OnClearScheduleClick"/>
+        </ContextMenu>
+      </Border.ContextMenu>
+      <Grid ColumnDefinitions="0,32,*,32" Margin="6,8,10,8">
 
       <!-- Done toggle -->
       <Button Grid.Column="1" Classes="flat" VerticalAlignment="Top"
@@ -53,6 +64,15 @@
             <TextBlock Text="{Binding Status}"/>
           </Border>
 
+          <!-- Dequeue button (only when Queued) -->
+          <Button Classes="icon-btn dequeue-btn"
+                  IsVisible="{Binding IsQueued}"
+                  ToolTip.Tip="Remove from queue"
+                  Command="{Binding $parent[ItemsControl].((vm:TasksIslandViewModel)DataContext).RemoveFromQueueCommand}"
+                  CommandParameter="{Binding}">
+            <PathIcon Width="10" Height="10" Data="{StaticResource Icon.X}"/>
+          </Button>
+
           <!-- List chip with dot -->
           <Border Classes="chip chip-list">
             <StackPanel Orientation="Horizontal" Spacing="5" VerticalAlignment="Center">
@@ -129,5 +149,45 @@
       <Border Height="2" VerticalAlignment="Center" Margin="4,0"
               Background="{DynamicResource MossBrush}" CornerRadius="1"/>
     </Grid>
+
+    <!-- Hidden schedule anchor (its Flyout is shown from the context menu) -->
+    <Button Grid.Row="1" x:Name="ScheduleAnchor"
+            Width="1" Height="1" Opacity="0"
+            HorizontalAlignment="Left" VerticalAlignment="Top"
+            IsHitTestVisible="False" Focusable="False">
+      <Button.Flyout>
+        <Flyout Placement="Bottom" ShowMode="Standard">
+          <Border Background="{DynamicResource Surface2Brush}"
+                  BorderBrush="{DynamicResource BorderBrush}"
+                  BorderThickness="1" CornerRadius="10"
+                  Padding="16" Width="300">
+            <StackPanel Spacing="12">
+              <TextBlock Text="Schedule task"
+                         FontWeight="SemiBold" FontSize="13"
+                         Foreground="{DynamicResource TextBrush}"/>
+
+              <StackPanel Spacing="6">
+                <TextBlock Text="DATE" FontSize="10" Opacity="0.6"
+                           Foreground="{DynamicResource TextDimBrush}"/>
+                <DatePicker x:Name="ScheduleDate" HorizontalAlignment="Stretch"/>
+              </StackPanel>
+
+              <StackPanel Spacing="6">
+                <TextBlock Text="TIME" FontSize="10" Opacity="0.6"
+                           Foreground="{DynamicResource TextDimBrush}"/>
+                <TimePicker x:Name="ScheduleTime" ClockIdentifier="24HourClock"
+                            HorizontalAlignment="Stretch"/>
+              </StackPanel>
+
+              <StackPanel Orientation="Horizontal" Spacing="8"
+                          HorizontalAlignment="Right" Margin="0,4,0,0">
+                <Button Content="Cancel" Click="OnScheduleCancelClick" MinWidth="76"/>
+                <Button Content="Schedule" Classes="accent" Click="OnScheduleSetClick" MinWidth="76"/>
+              </StackPanel>
+            </StackPanel>
+          </Border>
+        </Flyout>
+      </Button.Flyout>
+    </Button>
   </Grid>
 </UserControl>