Add Feature: Monatsübersicht Fehlzeiten Widget

LehrerApp.Desktop/Views/ClassTeacher/ClassTeacherOverviewView.axaml

@@ -98,6 +98,19 @@
     <Style Selector="Border.statusFill.danger">
       <Setter Property="Background" Value="{DynamicResource AppStatusDangerBrush}"/>
     </Style>
+    <Style Selector="Border.compactDay">
+      <Setter Property="Width" Value="28"/>
+      <Setter Property="Height" Value="28"/>
+      <Setter Property="CornerRadius" Value="6"/>
+      <Setter Property="Background" Value="{DynamicResource AppChipBackgroundBrush}"/>
+      <Setter Property="BorderBrush" Value="{DynamicResource AppCardBorderBrush}"/>
+      <Setter Property="BorderThickness" Value="1"/>
+      <Setter Property="Margin" Value="2"/>
+    </Style>
+    <Style Selector="Border.compactDay.today">
+      <Setter Property="BorderBrush" Value="{DynamicResource AppAccentTextBrush}"/>
+      <Setter Property="BorderThickness" Value="2"/>
+    </Style>
   </UserControl.Styles>
 
   <UserControl.Resources>
@@ -409,6 +422,48 @@
                   </StackPanel>
                 </Border>
 
+                <!-- Verdichtete Monatsansicht: exakt eine Zelle je Kalendertag. Ohne Ereignis
+                     bleibt nur die Tageszahl sichtbar; bei Auffälligkeiten ersetzt das stärkste
+                     Statuskürzel die Zahl. Alle Details bleiben per Tooltip und Drill-down erhalten. -->
+                <Border Classes="sidePanel">
+                  <StackPanel Spacing="8">
+                    <Grid ColumnDefinitions="*,Auto">
+                      <StackPanel>
+                        <TextBlock Text="Monat auf einen Blick" FontSize="14" FontWeight="SemiBold"/>
+                        <TextBlock Text="{Binding CompactMonthLabel}" FontSize="11" Opacity="0.55"/>
+                      </StackPanel>
+                      <Button Grid.Column="1" Content="Öffnen ›" Command="{Binding OpenMonthlyCalendarCommand}"
+                              Background="Transparent" BorderThickness="0" Padding="6,2"
+                              Foreground="{DynamicResource AppAccentTextBrush}"/>
+                    </Grid>
+                    <ItemsControl ItemsSource="{Binding CompactMonthDays}" HorizontalAlignment="Center">
+                      <ItemsControl.ItemsPanel>
+                        <ItemsPanelTemplate><UniformGrid Columns="7"/></ItemsPanelTemplate>
+                      </ItemsControl.ItemsPanel>
+                      <ItemsControl.ItemTemplate>
+                        <DataTemplate x:DataType="vm:ClassTeacherCompactCalendarDay">
+                          <Border Classes="compactDay" Classes.today="{Binding IsToday}"
+                                  ToolTip.Tip="{Binding Tooltip}">
+                            <Grid>
+                              <TextBlock Text="{Binding DayNumber}" FontSize="11" Opacity="0.7"
+                                         HorizontalAlignment="Center" VerticalAlignment="Center"
+                                         IsVisible="{Binding !HasSignal}"/>
+                              <Border Background="{Binding SignalColorHex}" CornerRadius="5"
+                                      IsVisible="{Binding HasSignal}">
+                                <TextBlock Text="{Binding SignalCode}" Foreground="White" FontSize="11"
+                                           FontWeight="Bold" HorizontalAlignment="Center"
+                                           VerticalAlignment="Center"/>
+                              </Border>
+                            </Grid>
+                          </Border>
+                        </DataTemplate>
+                      </ItemsControl.ItemTemplate>
+                    </ItemsControl>
+                    <TextBlock Text="U unentsch. · ! Klassenbuch · A abwesend · V verspätet · E entsch."
+                               FontSize="9" Opacity="0.5" TextWrapping="Wrap"/>
+                  </StackPanel>
+                </Border>
+
                 <Border Classes="sidePanel" IsVisible="{Binding HasOpenExcuses}">
                   <StackPanel Spacing="8">
                     <TextBlock Text="Offene Entschuldigungen" FontSize="14" FontWeight="SemiBold"/>