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/clear_screen.md

@@ -0,0 +1,32 @@
+---
+name: clear_screen
+kind: function
+lang: go
+domain: tui
+version: "1.0.0"
+purity: pure
+signature: "func ClearScreen() string"
+description: "Devuelve el codigo de escape ANSI para limpiar la pantalla del terminal."
+tags: [tui, ansi, terminal, screen]
+uses_functions: []
+uses_types: []
+returns: []
+returns_optional: false
+error_type: ""
+imports: []
+tested: false
+tests: []
+test_file_path: ""
+file_path: "functions/tui/clear_screen.go"
+---
+
+## Ejemplo
+
+```go
+fmt.Print(ClearScreen())
+// Limpia toda la pantalla y mueve el cursor a la posicion inicial
+```
+
+## Notas
+
+Combina ESC[2J (borrar pantalla completa) con ESC[H (mover cursor a home). No tiene side effects: solo devuelve el string ANSI.