Add CI/CD Pipeline with NuGet Publishing

[StevenTCramer]

Summary

This PR implements a complete CI/CD pipeline for automated NuGet package publishing.

Changes

CI/CD Implementation

• ✅ Created modular PowerShell scripts in CI-CD/ folder for easy local testing
• ✅ Built GitHub Actions workflow that calls PowerShell scripts
• ✅ Preserved all functionality from original publish.ps1 script

Key Features

• PowerShell-First Approach: Easy local testing without GitHub Actions overhead
• Modular Design: Can run individual phases (build, publish, or all)
• Enhanced Error Handling: Colored output and comprehensive logging
• Secure API Key Management: Via environment variables and GitHub Secrets
• Conditional Publishing: Only on GitHub releases
• Clean Builds: All warnings resolved (IL2070, NU5100)
• Proper Test Execution: Using dotnet fixie instead of dotnet test

Files Added

• CI-CD/ci-cd.ps1 - Main orchestration script
• CI-CD/build-and-test.ps1 - Build and test phase
• CI-CD/publish-nuget.ps1 - NuGet publishing phase
• CI-CD/README.md - Comprehensive documentation
• .github/workflows/ci-cd.yml - GitHub Actions workflow

Testing Results

• ✅ Local build test successful: 12 tests passed, 1 skipped
• ✅ Package creation successful: TimeWarp.Fixie.3.1.0.nupkg
• ✅ Zero warnings in build output
• ✅ All functionality preserved from original publish script

Testing the CI/CD

This PR should trigger the new CI/CD workflow to test the build and test phase. The publish phase will only run on releases.

Related Tasks

• Completes Kanban task 002: Add NuGet Publishing to CI/CD workflow
• Builds on task 001: Class-Specific ConfigureServices implementation