feat(ui): tasks island with rows, chips, add-task, selection

TaskRowView with status chip (EqStatus converter + parameter),
StrikeIfTrue, NotNullToBool converters. TasksIslandView with header,
add-task TextBox (Enter=AddCommand), ItemsControl + flat Button for
selection. Converters registered in App.axaml.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/ClaudeDo.App/App.axaml

@@ -2,6 +2,7 @@
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
              x:Class="ClaudeDo.App.App"
              xmlns:local="using:ClaudeDo.App"
+             xmlns:converters="using:ClaudeDo.Ui.Converters"
              RequestedThemeVariant="Dark">
 
     <Application.Resources>
@@ -10,6 +11,11 @@
                 <ResourceInclude Source="avares://ClaudeDo.Ui/Design/Tokens.axaml" />
             </ResourceDictionary.MergedDictionaries>
 
+            <!-- Converters -->
+            <converters:NotNullToBoolConverter x:Key="NotNullToBool"/>
+            <converters:StrikeIfTrueConverter  x:Key="StrikeIfTrue"/>
+            <converters:EqStatusConverter      x:Key="EqStatus"/>
+
             <!-- Accent: Forest Teal -->
             <SolidColorBrush x:Key="AccentBrush" Color="#3d9474"/>
             <SolidColorBrush x:Key="AccentLightBrush" Color="#6bb89e"/>