Initial samples: TodoApp and ShellDemo

Two sample applications demonstrating OpenMaui Linux:

TodoApp:
- Full task manager with NavigationPage
- CollectionView with XAML data binding
- DisplayAlert dialogs
- Grid layouts with star sizing

ShellDemo:
- Comprehensive control showcase
- Shell with flyout navigation
- All core MAUI controls demonstrated
- Real-time event logging

Both samples reference OpenMaui.Controls.Linux via NuGet.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

TodoApp/TodoApp.csproj

@@ -0,0 +1,15 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net9.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+    <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="OpenMaui.Controls.Linux" Version="1.0.0-preview.*" />
+  </ItemGroup>
+
+</Project>