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.cs

@@ -25,6 +25,8 @@ public partial class SessionTerminalView : UserControl
         AvaloniaProperty.Register<SessionTerminalView, string?>(nameof(ComposerText), defaultBindingMode: BindingMode.TwoWay);
     public static readonly StyledProperty<ICommand?> SubmitCommandProperty =
         AvaloniaProperty.Register<SessionTerminalView, ICommand?>(nameof(SubmitCommand));
+    public static readonly StyledProperty<ICommand?> InterruptCommandProperty =
+        AvaloniaProperty.Register<SessionTerminalView, ICommand?>(nameof(InterruptCommand));
     public static readonly StyledProperty<string?> ComposerPlaceholderProperty =
         AvaloniaProperty.Register<SessionTerminalView, string?>(nameof(ComposerPlaceholder));
 
@@ -36,6 +38,7 @@ public partial class SessionTerminalView : UserControl
     public bool IsComposerVisible { get => GetValue(IsComposerVisibleProperty); set => SetValue(IsComposerVisibleProperty, value); }
     public string? ComposerText { get => GetValue(ComposerTextProperty); set => SetValue(ComposerTextProperty, value); }
     public ICommand? SubmitCommand { get => GetValue(SubmitCommandProperty); set => SetValue(SubmitCommandProperty, value); }
+    public ICommand? InterruptCommand { get => GetValue(InterruptCommandProperty); set => SetValue(InterruptCommandProperty, value); }
     public string? ComposerPlaceholder { get => GetValue(ComposerPlaceholderProperty); set => SetValue(ComposerPlaceholderProperty, value); }
 
     private INotifyCollectionChanged? _subscribedCollection;