Add README files to NuGet packages (#677)

* Initial plan

* Add README files to NuGet packages for Semi.Avalonia, Semi.Avalonia.DataGrid, and Semi.Avalonia.ColorPicker

Co-authored-by: rabbitism <14807942+rabbitism@users.noreply.github.com>

* Restore Package.props import to reduce code duplication

Co-authored-by: rabbitism <14807942+rabbitism@users.noreply.github.com>

* Add README file to Semi.Avalonia.TreeDataGrid package

Co-authored-by: zdpcdt <54255897+zdpcdt@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: rabbitism <14807942+rabbitism@users.noreply.github.com>
Co-authored-by: zdpcdt <54255897+zdpcdt@users.noreply.github.com>

src/Semi.Avalonia.TreeDataGrid/README.md

@@ -0,0 +1,49 @@
+# Semi.Avalonia.TreeDataGrid
+
+[![Semi Avalonia](https://img.shields.io/nuget/v/Semi.Avalonia.svg?color=red&style=flat-square)](https://www.nuget.org/packages/Semi.Avalonia/)
+
+Avalonia TreeDataGrid Theme inspired by Semi Design
+
+This package provides Semi Design theming for the Avalonia TreeDataGrid control.
+
+## Installation
+
+```bash
+dotnet add package Semi.Avalonia.TreeDataGrid
+```
+
+## Prerequisites
+
+This package requires the main Semi.Avalonia theme to be installed:
+
+```bash
+dotnet add package Semi.Avalonia
+```
+
+## Usage
+
+Include the TreeDataGrid theme in your application:
+
+```xaml
+<Application
+    ...
+    xmlns:semi="https://irihi.tech/semi">
+    <Application.Styles>
+        <semi:SemiTheme Locale="zh-CN" />
+        <semi:TreeDataGridSemiTheme />
+    </Application.Styles>
+</Application>
+```
+
+## Resources
+
+- [Documentation](https://docs.irihi.tech/semi/)
+- [Repository](https://github.com/irihitech/Semi.Avalonia)
+- [Online Demo](https://irihitech.github.io/Semi.Avalonia/)
+- [Download Demo](https://github.com/irihitech/Semi.Avalonia/releases)
+
+## Credits
+
+[Semi Design](https://semi.design/)
+
+[Avalonia](https://github.com/AvaloniaUI/Avalonia)

src/Semi.Avalonia.TreeDataGrid/Semi.Avalonia.TreeDataGrid.csproj

@@ -12,6 +12,7 @@
         <PackageLicenseExpression>MIT</PackageLicenseExpression>
         <PackageIcon>irihi.png</PackageIcon>
         <PackageProjectUrl>https://github.com/irihitech/Semi.Avalonia</PackageProjectUrl>
+        <PackageReadmeFile>README.md</PackageReadmeFile>
     </PropertyGroup>
 
     <PropertyGroup Condition="$([MSBuild]::IsTargetFrameworkCompatible('$(TargetFramework)', 'net8.0'))">
@@ -22,6 +23,7 @@
         <PackageReference Include="Avalonia.Controls.TreeDataGrid" Version="11.0.10"/>
         <None Include="..\..\irihi.png" Pack="true" PackagePath="\" Link="Properties\irihi.png"/>
         <None Include="..\..\LICENSE" Pack="true" PackagePath="\" Link="Properties\LICENSE"/>
+        <None Include="README.md" Pack="true" PackagePath="\" />
     </ItemGroup>
 
 </Project>