- Add csharp job: builds with Mono, tests sync version
- Add dotnet job: builds both sync and async with .NET 10
- Update clients/dotnet/Makefile to support sync and async builds
- Update clients/csharp/Makefile to remove reference to deleted dotnet folder
- Add both to summary job dependencies
- Single-file Un.cs using modern C# features
- Top-level statements, HttpClient, System.Text.Json
- Full feature parity with Mono version (648 lines vs 1260)
- Supports execute, session, service, service env, key commands