Move UI & make a root model.

Signed-off-by: Hadi <112569860+anotherhadi@users.noreply.github.com>

main.go

@@ -6,7 +6,6 @@ import (
 
 	tea "charm.land/bubbletea/v2"
 	"github.com/anotherhadi/usbguard-tui/internal/guard"
-	"github.com/anotherhadi/usbguard-tui/internal/ui"
 )
 
 var version = "dev"
@@ -22,7 +21,7 @@ func main() {
 		os.Exit(1)
 	}
 
-	p := tea.NewProgram(ui.New())
+	p := tea.NewProgram(newApp())
 	if _, err := p.Run(); err != nil {
 		fmt.Fprintln(os.Stderr, err)
 		os.Exit(1)