feat(ui): Mission Control Recent Sessions mit verschachtelten Handoffs

Neue Tabelle mission_control_sessions (Migration AddMissionControlSessions), befuellt vom
InteractiveLaunchSpecService bei Task-, Ad-hoc- und Handoff-Kacheln. Flyout im Mission-Control-Header
listet die letzten 14 Tage / 50 Sessions, Handoffs eingerueckt unter ihrer Ursprungs-Session, mit
Fortsetzen (--resume im gespeicherten cwd) und Brief anzeigen.

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

@@ -48,6 +48,60 @@
               </MenuFlyout>
             </Button.Flyout>
           </Button>
+          <Button x:Name="RecentSessionsButton" Classes="icon-btn"
+                  ToolTip.Tip="{loc:Tr missionControl.recentSessions}">
+            <PathIcon Data="{StaticResource Icon.Clock}" Width="15" Height="15"/>
+            <Button.Flyout>
+              <Flyout Placement="BottomEdgeAlignedRight" ShowMode="Standard" Opening="OnRecentSessionsFlyoutOpening">
+                <StackPanel Width="380" Spacing="8" Margin="4">
+                  <TextBlock Classes="eyebrow"
+                             Text="{loc:Tr missionControl.recentSessions}"
+                             Foreground="{DynamicResource TextMuteBrush}"
+                             LetterSpacing="1.4" />
+                  <TextBlock Classes="meta"
+                             Text="{loc:Tr missionControl.recentSessionsEmpty}"
+                             IsVisible="{Binding !HasRecentSessions}"
+                             Foreground="{DynamicResource TextMuteBrush}" />
+                  <ScrollViewer MaxHeight="420">
+                    <ItemsControl x:Name="RecentSessionsList" ItemsSource="{Binding RecentSessions}">
+                      <ItemsControl.Styles>
+                        <Style Selector="Grid.handoff">
+                          <Setter Property="Margin" Value="{StaticResource NestedRowIndent}" />
+                        </Style>
+                      </ItemsControl.Styles>
+                      <ItemsControl.ItemTemplate>
+                        <DataTemplate x:DataType="vm:RecentSessionViewModel">
+                          <Grid ColumnDefinitions="*,Auto" Classes.handoff="{Binding IsHandoff}">
+                            <StackPanel Grid.Column="0" Spacing="2" Margin="0,4" VerticalAlignment="Center">
+                              <TextBlock Text="{Binding Title}"
+                                         TextTrimming="CharacterEllipsis"
+                                         ToolTip.Tip="{Binding Title}"
+                                         Foreground="{DynamicResource TextDimBrush}" />
+                              <TextBlock Classes="meta"
+                                         Text="{Binding Meta}"
+                                         TextTrimming="CharacterEllipsis"
+                                         ToolTip.Tip="{Binding Meta}"
+                                         Foreground="{DynamicResource TextMuteBrush}" />
+                            </StackPanel>
+                            <StackPanel Grid.Column="1" Orientation="Horizontal" Spacing="4"
+                                        VerticalAlignment="Center">
+                              <Button Classes="btn"
+                                      Content="{loc:Tr missionControl.showBrief}"
+                                      Command="{Binding ShowBriefCommand}"
+                                      IsVisible="{Binding HasBrief}" />
+                              <Button Classes="btn"
+                                      Content="{loc:Tr missionControl.resumeSession}"
+                                      Command="{Binding ResumeCommand}" />
+                            </StackPanel>
+                          </Grid>
+                        </DataTemplate>
+                      </ItemsControl.ItemTemplate>
+                    </ItemsControl>
+                  </ScrollViewer>
+                </StackPanel>
+              </Flyout>
+            </Button.Flyout>
+          </Button>
           <Button Classes="icon-btn"
                   Command="{Binding ToggleLayoutCommand}"
                   ToolTip.Tip="{Binding LayoutToggleLabel}">

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

@@ -29,10 +29,14 @@ public partial class MissionControlView : UserControl
         InitializeComponent();
         DataContextChanged += OnDataContextChanged;
         QueueSplitter.DragCompleted += (_, _) => _queueWidth = BodyGrid.ColumnDefinitions[2].Width;
+        // Resume/Brief buttons don't close a plain Flyout on their own.
+        RecentSessionsList.AddHandler(Button.ClickEvent, (_, _) => RecentSessionsButton.Flyout?.Hide());
     }
 
     private void OnSessionFlyoutOpening(object? sender, EventArgs e) => _ = _vm?.RefreshSessionTargetsAsync();
 
+    private void OnRecentSessionsFlyoutOpening(object? sender, EventArgs e) => _ = _vm?.RefreshRecentSessionsAsync();
+
     // Ad-hoc ConPTY session: the view owns the folder picker, the VM only takes the chosen path.
     private async void BrowseForSessionAsync()
     {