fix(ui): NAVIGATOR eyebrow — drop broken converter binding

The Binding had no Path, so it bound to ListsIslandViewModel itself
and the UpperCase converter produced the fully-qualified type name,
which rendered as "CLAUDEDO.UI.VIEWMODELS.ISLAI..." in the header.
Replace with literal Text="NAVIGATOR".

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

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

@@ -16,11 +16,9 @@
     <Border DockPanel.Dock="Top" Classes="island-header">
       <StackPanel Margin="14,12,14,0" Spacing="4">
         <TextBlock Classes="eyebrow"
-                   Text="{Binding Converter={StaticResource UpperCase}, ConverterParameter=Navigator, FallbackValue=NAVIGATOR}"
+                   Text="NAVIGATOR"
                    FontFamily="{DynamicResource MonoFont}" FontSize="9"
-                   Foreground="{DynamicResource TextFaintBrush}" LetterSpacing="1.2">
-          <TextBlock.Text>NAVIGATOR</TextBlock.Text>
-        </TextBlock>
+                   Foreground="{DynamicResource TextFaintBrush}" LetterSpacing="1.2"/>
         <TextBlock FontFamily="{DynamicResource SansFamily}" FontSize="18"
                    FontWeight="SemiBold" Foreground="{DynamicResource TextBrush}"
                    Text="Lists"/>