Simplify setup to Ubuntu-only with install script

Co-authored-by: jongalloway <[email protected]>

Author: Copilot

copilot-setup-steps.yml

@@ -6,7 +6,7 @@ description: Install .NET 9 SDK and restore dependencies for the NLWebNet librar
 
 steps:
   - name: Install .NET 9 SDK
-    description: Install the .NET 9 SDK using the official Microsoft installation methods
+    description: Download and install the .NET 9 SDK for Ubuntu using the official Microsoft install script
     run: |
       # Check if .NET 9 is already installed
       if command -v dotnet &> /dev/null && dotnet --list-sdks | grep -q "9\."; then
@@ -15,34 +15,14 @@ steps:
         exit 0
       fi
       
-      # Install .NET 9 SDK using official Microsoft methods
+      # Download and install .NET 9 SDK using official Microsoft install script
       echo "📦 Installing .NET 9 SDK..."
+      curl -sSL https://dot.net/v1/dotnet-install.sh | bash /dev/stdin --channel 9.0 --install-dir ~/.dotnet
       
-      # For Ubuntu/Debian
-      if command -v apt &> /dev/null; then
-        # Add Microsoft package repository
-        wget https://packages.microsoft.com/config/ubuntu/$(lsb_release -rs)/packages-microsoft-prod.deb -O packages-microsoft-prod.deb
-        sudo dpkg -i packages-microsoft-prod.deb
-        rm packages-microsoft-prod.deb
-        
-        # Install .NET 9 SDK
-        sudo apt update
-        sudo apt install -y dotnet-sdk-9.0
-      
-      # For macOS with Homebrew
-      elif command -v brew &> /dev/null; then
-        brew install dotnet
-      
-      # For other systems, use the official install script (same as GitHub Actions uses internally)
-      else
-        echo "Using official Microsoft .NET install script..."
-        curl -sSL https://dot.net/v1/dotnet-install.sh | bash /dev/stdin --channel 9.0 --install-dir ~/.dotnet
-        
-        # Add .NET to PATH if not already present
-        if [[ ":$PATH:" != *":$HOME/.dotnet:"* ]]; then
-          echo 'export PATH="$HOME/.dotnet:$PATH"' >> ~/.bashrc
-          export PATH="$HOME/.dotnet:$PATH"
-        fi
+      # Add .NET to PATH if not already present
+      if [[ ":$PATH:" != *":$HOME/.dotnet:"* ]]; then
+        echo 'export PATH="$HOME/.dotnet:$PATH"' >> ~/.bashrc
+        export PATH="$HOME/.dotnet:$PATH"
       fi
       
       # Verify installation