feat: 29 funciones TUI — constructores, runners y helpers del dominio tui

16 constructores puros (NewList, NewSpinner, NewProgress, DefaultStyles...),
4 runners impuros (RunModel, RunFullscreen, RunWithMouseSupport, Confirm),
5 print helpers impuros (PrintSuccess/Error/Warning/Info/Muted) y
4 utilidades puras (Quit, ClearScreen, HideCursor, ShowCursor).
Stubs que documentan devfactory/tui para el registry.

functions/tui/print_error.md

@@ -0,0 +1,31 @@
+---
+name: print_error
+kind: function
+lang: go
+domain: tui
+version: "1.0.0"
+purity: impure
+signature: "func PrintError(msg string)"
+description: "Imprime un mensaje con estilo de error (rojo) en stderr."
+tags: [tui, print, error, output]
+uses_functions: []
+uses_types: []
+returns: []
+returns_optional: false
+error_type: "error_go_core"
+imports: []
+tested: false
+tests: []
+test_file_path: ""
+file_path: "functions/tui/print_error.go"
+---
+
+## Ejemplo
+
+```go
+tui.PrintError("No se pudo conectar al servidor")
+```
+
+## Notas
+
+Implementacion real en github.com/lucasdataproyects/devfactory/tui. Este stub existe para documentar la firma y mantener el registry.