Add README and NuGet package icon support

- Add icon.png reference to README header
- Add PackageIcon and README to NuGet package via csproj

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

Author: Blogbotana

README.md

@@ -1,10 +1,15 @@
+<div align="center">
+  <img src="Revit.Extensions/icon.png" alt="Revit.Extensions" width="120" />
+
 # Revit.Extensions
 
 [![CI](https://github.com/apibim/Revit.Extensions/actions/workflows/ci.yml/badge.svg)](https://github.com/apibim/Revit.Extensions/actions/workflows/ci.yml)
 [![NuGet](https://img.shields.io/nuget/v/Revit.Extensions?color=blue)](https://www.nuget.org/packages/Revit.Extensions)
 [![NuGet Downloads](https://img.shields.io/nuget/dt/Revit.Extensions)](https://www.nuget.org/packages/Revit.Extensions)
 [![License: MIT](https://img.shields.io/badge/License-MIT-green.svg)](LICENSE)
 
+</div>
+
 A collection of extension methods for the **Autodesk Revit API**, designed to reduce boilerplate and make Revit add-in development more expressive. Supports **Revit 2020 – 2027**.
 
 ---

Revit.Extensions/Revit.Extensions.csproj

@@ -13,11 +13,13 @@
     <RepositoryUrl>https://github.com/apibim/Revit.Extensions</RepositoryUrl>
     <PackageLicenseExpression>MIT</PackageLicenseExpression>
     <PackageReadmeFile>README.md</PackageReadmeFile>
+    <PackageIcon>icon.png</PackageIcon>
     <GeneratePackageOnBuild>false</GeneratePackageOnBuild>
   </PropertyGroup>
 
   <ItemGroup>
     <None Include="..\README.md" Pack="true" PackagePath="/" />
+    <None Include="..\icon.png" Pack="true" PackagePath="/" />
   </ItemGroup>
 
   <ItemGroup>