feat(branding): add app and installer icons

- app: ClaudeTask.ico wired as ApplicationIcon and MainWindow.Icon
  via avares URI
- installer: ClaudeTaskSetup.ico wired as ApplicationIcon and embedded
  as a WPF Resource so WizardWindow and SettingsWindow can reference it
  via pack URI

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/ClaudeDo.Installer/ClaudeDo.Installer.csproj

@@ -8,8 +8,14 @@
     <ImplicitUsings>enable</ImplicitUsings>
     <!-- Allow Linux Gitea runners to publish this WPF project for win-x64; no-op on Windows. -->
     <EnableWindowsTargeting>true</EnableWindowsTargeting>
+    <ApplicationIcon>ClaudeTaskSetup.ico</ApplicationIcon>
   </PropertyGroup>
 
+  <ItemGroup>
+    <!-- Embed icon so it is available via pack URI in WPF windows. -->
+    <Resource Include="ClaudeTaskSetup.ico" />
+  </ItemGroup>
+
   <!-- Debug: asInvoker so Rider/VS can debug without elevation -->
   <PropertyGroup Condition="'$(Configuration)' == 'Debug'">
     <ApplicationManifest>app.debug.manifest</ApplicationManifest>

src/ClaudeDo.Installer/Views/SettingsWindow.xaml

@@ -3,6 +3,7 @@
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:views="clr-namespace:ClaudeDo.Installer.Views"
         Title="ClaudeDo Settings"
+        Icon="/ClaudeTaskSetup.ico"
         Width="720" Height="520"
         MinWidth="620" MinHeight="460"
         WindowStartupLocation="CenterScreen"

src/ClaudeDo.Installer/Views/WizardWindow.xaml

@@ -3,6 +3,7 @@
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:views="clr-namespace:ClaudeDo.Installer.Views"
         Title="ClaudeDo Installer"
+        Icon="/ClaudeTaskSetup.ico"
         Width="720" Height="520"
         MinWidth="620" MinHeight="460"
         WindowStartupLocation="CenterScreen"