git: a creation gate that never writes history, a git tab with Paperclip's worktree scan, and a warning line in every pane

tui/main.go

@@ -40,6 +40,14 @@ func main() {
 		fmt.Fprintln(os.Stderr, "warning: PAPERCLIP_BOARD_KEY is not set, so replies and status changes will be refused")
 	}
 
+	// One git read, here, before the terminal is taken over: the banner in every
+	// pane depends on it and no git command may run inside Update or View.
+	screenFolder := *folder
+	if screenFolder == "" {
+		screenFolder, _ = os.Getwd()
+	}
+	setGitBanner(screenFolder)
+
 	var m tea.Model
 	switch *screen {
 	case "board":
@@ -138,7 +146,8 @@ func main() {
 
 	// Alternate screen: TUIOS keeps its own scrollback, and a full-screen
 	// program that redraws in place must not fight it.
-	p := tea.NewProgram(m, tea.WithAltScreen(), tea.WithMouseCellMotion())
+	// The setup warning is drawn once for the whole screen, not once per panel.
+	p := tea.NewProgram(bannerModel{inner: m}, tea.WithAltScreen(), tea.WithMouseCellMotion())
 	if _, err := p.Run(); err != nil {
 		fmt.Fprintln(os.Stderr, err)
 		os.Exit(1)