feat: Add ARM64 builds and universal installation script

- Add ARM64 builds for all platforms (Windows, Linux, macOS) in release workflow
- Create universal installation script (install.sh) with automatic platform detection
- Implement smart fallback from ARM64 to x64 when ARM64 builds unavailable
- Add checksum verification for secure downloads
- Support both user and system-wide installation modes
- Update README.md with new installation methods and ARM64 support documentation
- Maintain backward compatibility with existing x64 builds

Fixes #45

Author: jbrinkman

.github/workflows/release.yml

@@ -30,21 +30,36 @@ jobs:
 
       - name: Publish
         run: |
+          # x64 builds
           dotnet publish src/DotNetApiDiff/DotNetApiDiff.csproj --configuration Release --output ./publish/win-x64 --runtime win-x64 --self-contained true -p:PublishSingleFile=true -p:Version=${GITHUB_REF#refs/tags/v}
           dotnet publish src/DotNetApiDiff/DotNetApiDiff.csproj --configuration Release --output ./publish/linux-x64 --runtime linux-x64 --self-contained true -p:PublishSingleFile=true -p:Version=${GITHUB_REF#refs/tags/v}
           dotnet publish src/DotNetApiDiff/DotNetApiDiff.csproj --configuration Release --output ./publish/osx-x64 --runtime osx-x64 --self-contained true -p:PublishSingleFile=true -p:Version=${GITHUB_REF#refs/tags/v}
 
+          # ARM64 builds
+          dotnet publish src/DotNetApiDiff/DotNetApiDiff.csproj --configuration Release --output ./publish/win-arm64 --runtime win-arm64 --self-contained true -p:PublishSingleFile=true -p:Version=${GITHUB_REF#refs/tags/v}
+          dotnet publish src/DotNetApiDiff/DotNetApiDiff.csproj --configuration Release --output ./publish/linux-arm64 --runtime linux-arm64 --self-contained true -p:PublishSingleFile=true -p:Version=${GITHUB_REF#refs/tags/v}
+          dotnet publish src/DotNetApiDiff/DotNetApiDiff.csproj --configuration Release --output ./publish/osx-arm64 --runtime osx-arm64 --self-contained true -p:PublishSingleFile=true -p:Version=${GITHUB_REF#refs/tags/v}
+
       - name: Create ZIP archives
         run: |
+          # x64 archives
           cd ./publish/win-x64 && zip -r ../../dotnet-api-diff-win-x64.zip . && cd ../..
           cd ./publish/linux-x64 && tar -czf ../../dotnet-api-diff-linux-x64.tar.gz . && cd ../..
           cd ./publish/osx-x64 && tar -czf ../../dotnet-api-diff-osx-x64.tar.gz . && cd ../..
 
+          # ARM64 archives
+          cd ./publish/win-arm64 && zip -r ../../dotnet-api-diff-win-arm64.zip . && cd ../..
+          cd ./publish/linux-arm64 && tar -czf ../../dotnet-api-diff-linux-arm64.tar.gz . && cd ../..
+          cd ./publish/osx-arm64 && tar -czf ../../dotnet-api-diff-osx-arm64.tar.gz . && cd ../..
+
       - name: Create Release
         uses: softprops/action-gh-release@v1
         with:
           files: |
             dotnet-api-diff-win-x64.zip
             dotnet-api-diff-linux-x64.tar.gz
             dotnet-api-diff-osx-x64.tar.gz
+            dotnet-api-diff-win-arm64.zip
+            dotnet-api-diff-linux-arm64.tar.gz
+            dotnet-api-diff-osx-arm64.tar.gz
           generate_release_notes: true

README.md

@@ -87,6 +87,31 @@ task ci
 
 ### Installation
 
+#### Quick Install (Linux/macOS)
+
+```bash
+# Install latest version to user directory
+curl -fsSL https://raw.githubusercontent.com/jbrinkman/dotnet-api-diff/main/install.sh | bash
+
+# Install specific version
+curl -fsSL https://raw.githubusercontent.com/jbrinkman/dotnet-api-diff/main/install.sh | bash -s -- v1.2.3
+
+# Install system-wide (requires sudo)
+curl -fsSL https://raw.githubusercontent.com/jbrinkman/dotnet-api-diff/main/install.sh | sudo bash -s -- --system
+```
+
+#### Manual Install
+
+Download the latest release for your platform from [GitHub Releases](https://github.com/jbrinkman/dotnet-api-diff/releases):
+
+- **Linux**: `dotnet-api-diff-linux-x64.tar.gz` or `dotnet-api-diff-linux-arm64.tar.gz`
+- **macOS**: `dotnet-api-diff-osx-x64.tar.gz` or `dotnet-api-diff-osx-arm64.tar.gz` 
+- **Windows**: `dotnet-api-diff-win-x64.zip` or `dotnet-api-diff-win-arm64.zip`
+
+Extract the archive and add the binary to your PATH.
+
+#### Build from Source
+
 ```bash
 # Clone the repository
 git clone https://github.com/jbrinkman/dotnet-api-diff.git