dotnet-modernize Analyze existing .NET code for modernization opportunities. Identifies outdated target frameworks, deprecated packages, superseded API patterns, and missing modern best practices. Provides actionable recommendations for each finding. Scope boundary: This skill flags opportunities only. For actual migration paths, polyfill strategies, multi-targeting guidance, and step-by-step version upgrade procedures, see [skill:dotnet-version-upgrade] and [skill:dotnet-multi-targeting]. Prerequisites: Run [skill:dotnet-version-detection] first to determine the current SDK, TFM, and languag…