feat(ui): highlight user chat messages + opt-in interrupt (stop) button

LogKindForegroundConverter drives the log message foreground via a local
binding (beats the dim local value), so user messages render in the accent
color instead of vanishing into the transcript. Adds a small stop (Icon.Stop)
button next to Send in both composers (SessionTerminalView + WorkConsole) wired
to InterruptInteractiveCommand → InterruptInteractiveSessionAsync. Adds
session.composer.interrupt (en/de).

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

@@ -57,7 +57,7 @@
               BorderBrush="{DynamicResource LineBrush}"
               BorderThickness="0,1,0,0"
               Padding="6,5">
-        <Grid ColumnDefinitions="*,Auto">
+        <Grid ColumnDefinitions="*,Auto,Auto">
           <TextBox Grid.Column="0"
                    Text="{Binding #Root.ComposerText, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"
                    PlaceholderText="{Binding #Root.ComposerPlaceholder}"
@@ -67,6 +67,13 @@
             </TextBox.KeyBindings>
           </TextBox>
           <Button Grid.Column="1"
+                  Margin="6,0,0,0"
+                  Classes="title-ctrl"
+                  Command="{Binding #Root.InterruptCommand}"
+                  ToolTip.Tip="{loc:Tr session.composer.interrupt}">
+            <PathIcon Data="{StaticResource Icon.Stop}" Width="10" Height="10"/>
+          </Button>
+          <Button Grid.Column="2"
                   Margin="6,0,0,0"
                   Content="{loc:Tr session.composer.send}"
                   Command="{Binding #Root.SubmitCommand}"/>
@@ -89,7 +96,7 @@
                 <!-- Message text — selectable so the user can copy raw output -->
                 <SelectableTextBlock Grid.Column="1"
                                      Text="{Binding Text}" Tag="{Binding ClassName}"
-                                     Foreground="{DynamicResource TextDimBrush}"
+                                     Foreground="{Binding Kind, Converter={StaticResource LogKindForeground}}"
                                      TextWrapping="Wrap"/>
               </Grid>
             </DataTemplate>