dotnet-terminal-gui Terminal.Gui v2 for building full terminal user interfaces with windows, menus, dialogs, views, layout, event handling, color themes, and mouse support. Cross-platform across Windows, macOS, and Linux terminals. Version assumptions: .NET 8.0+ baseline. Terminal.Gui 2.0.0-alpha (v2 Alpha is the active development line for new projects -- API is stable with comprehensive features; breaking changes possible before Beta but core architecture is solid). v1.x (1.19.0) is in maintenance mode with no new features. Scope boundary: This skill owns full TUI application development wi…