Auto-formatter reordering of using statements across the solution. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Renamed OpenNest.Engine.Tests → OpenNest.Tests (directory, .csproj, namespaces in all .cs files). Added OpenNest.IO project reference. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>