feat(ui): Mission Control als Session-Hub

- "+" öffnet ein Menü mit allen Listen (working dir) statt direkt den
  Ordner-Dialog; "Ordner wählen…" bleibt als Fallback erste Zeile, damit
  das Menü auch bei fehlgeschlagener Listen-Abfrage nutzbar bleibt
- Rail-Rows: Kontextmenü "Sitzung öffnen" (gesperrt für Running — der
  Worktree gehört dort dem autonomen Lauf)
- Aktivitäts-Strip statt reiner Queue: WaitingForReview/Failed/Roadblock
  kommen dazu, Attention zuerst, unterschieden nur über Farbe (Aktionen
  bleiben in der Task-Detailansicht)

src/ClaudeDo.Ui/Views/MissionControl/MissionControlView.axaml

@@ -4,6 +4,7 @@
              xmlns:vmm="using:ClaudeDo.Ui.ViewModels.MissionControl"
              xmlns:mc="using:ClaudeDo.Ui.Views.MissionControl"
              xmlns:controls="using:ClaudeDo.Ui.Views.Controls"
+             xmlns:conv="using:ClaudeDo.Ui.Converters"
              xmlns:loc="using:ClaudeDo.Ui.Localization"
              x:DataType="vm:MissionControlViewModel"
              x:Class="ClaudeDo.Ui.Views.MissionControl.MissionControlView">
@@ -33,9 +34,19 @@
                                Margin="0,0,4,0"
                                VerticalAlignment="Center"/>
           <Button Classes="icon-btn"
-                  Click="OnNewSessionClicked"
                   ToolTip.Tip="{loc:Tr missionControl.newSession}">
             <PathIcon Data="{StaticResource Icon.Plus}" Width="15" Height="15"/>
+            <Button.Flyout>
+              <MenuFlyout ItemsSource="{Binding SessionTargets}" Opening="OnSessionFlyoutOpening">
+                <MenuFlyout.ItemContainerTheme>
+                  <ControlTheme TargetType="MenuItem" BasedOn="{StaticResource {x:Type MenuItem}}"
+                                x:DataType="vm:SessionTargetViewModel">
+                    <Setter Property="Header" Value="{Binding Label}"/>
+                    <Setter Property="Command" Value="{Binding StartCommand}"/>
+                  </ControlTheme>
+                </MenuFlyout.ItemContainerTheme>
+              </MenuFlyout>
+            </Button.Flyout>
           </Button>
           <Button Classes="icon-btn"
                   Command="{Binding ToggleLayoutCommand}"
@@ -100,7 +111,7 @@
               BorderThickness="1,0,0,0">
         <DockPanel LastChildFill="True" Margin="10,10">
           <TextBlock DockPanel.Dock="Top" Classes="eyebrow"
-                     Text="{loc:Tr missionControl.queue}"
+                     Text="{loc:Tr missionControl.activity}"
                      Foreground="{DynamicResource TextMuteBrush}"
                      LetterSpacing="1.4" Margin="0,0,0,8" />
           <ScrollViewer>
@@ -112,27 +123,31 @@
                           Background="Transparent" BorderThickness="0"
                           HorizontalAlignment="Stretch" HorizontalContentAlignment="Stretch"
                           Cursor="Hand">
+                    <Button.ContextMenu>
+                      <ContextMenu>
+                        <MenuItem Header="{loc:Tr missionControl.openSession}"
+                                  Command="{Binding OpenSessionCommand}"
+                                  IsEnabled="{Binding CanOpenSession}" />
+                      </ContextMenu>
+                    </Button.ContextMenu>
                     <Panel>
                       <Border Background="{DynamicResource SurfaceBrush}"
                               BorderBrush="{DynamicResource LineBrush}"
                               BorderThickness="1" CornerRadius="6" />
-                      <Border Background="{DynamicResource RunningTintBrush}"
-                              BorderBrush="{DynamicResource RunningTintBorderBrush}"
+                      <!-- Single state tint; brush keys come from the VM (Tokens.axaml). -->
+                      <Border Background="{Binding TintKey, Converter={x:Static conv:DotBrushConverter.Instance}}"
+                              BorderBrush="{Binding TintBorderKey, Converter={x:Static conv:DotBrushConverter.Instance}}"
                               BorderThickness="1" CornerRadius="6"
-                              IsVisible="{Binding IsRunning}" />
+                              IsVisible="{Binding TintKey, Converter={x:Static ObjectConverters.IsNotNull}}" />
                       <StackPanel Margin="8,6" Spacing="2">
                         <TextBlock Text="{Binding Title}"
                                    TextTrimming="CharacterEllipsis"
                                    ToolTip.Tip="{Binding Title}"
                                    Foreground="{DynamicResource TextDimBrush}" />
                         <TextBlock Classes="meta"
-                                   Text="{loc:Tr missionControl.blocked}"
-                                   IsVisible="{Binding IsBlocked}"
-                                   Foreground="{DynamicResource AmberBrush}" />
-                        <TextBlock Classes="meta"
-                                   Text="{loc:Tr missionControl.running}"
-                                   IsVisible="{Binding IsRunning}"
-                                   Foreground="{DynamicResource StatusRunningBrush}" />
+                                   Text="{Binding StatusLabel}"
+                                   IsVisible="{Binding StatusLabel, Converter={x:Static StringConverters.IsNotNullOrEmpty}}"
+                                   Foreground="{Binding StatusColorKey, Converter={x:Static conv:DotBrushConverter.Instance}}" />
                       </StackPanel>
                     </Panel>
                   </Button>