Add conditional execution to .NET Core Desktop workflow

[Copilot]

The workflow fails on repositories without .NET project files with MSBUILD : error MSB1003: Specify a project or solution file.

Changes

• Added detection step to check for .NET project files (.csproj, .sln, .vbproj, .fsproj)
• Gated all .NET build/test/package steps with conditional if: steps.check_dotnet.outputs.has_dotnet_files == 'true'
• Workflow now completes successfully when no .NET projects exist

- name: Check for .NET project files
  id: check_dotnet
  shell: pwsh
  run: |
    $projectFiles = Get-ChildItem -Path . -Recurse -Include *.csproj,*.sln,*.vbproj,*.fsproj -ErrorAction SilentlyContinue
    if ($projectFiles.Count -gt 0) {
      echo "has_dotnet_files=true" >> $env:GITHUB_OUTPUT
    } else {
      echo "has_dotnet_files=false" >> $env:GITHUB_OUTPUT
    }

- name: Install .NET Core
  if: steps.check_dotnet.outputs.has_dotnet_files == 'true'
  uses: actions/setup-dotnet@v4

Original prompt

Reference: https://github.com/frozen9993-droid/228/actions/runs/21092638909/job/60666000781#step:1:1

---

💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.