Method replaceBanner

internal/ui/program.go:868–879

replaceBanner regenerates the banner with the current shine column and splices it into place inside m.output. Anything written after the banner (the user's first prompt, agent output, etc.) is preserved — replaceBanner only rewrites the leading byte range that bannerEnd points at. Width comes from m

()

// comes from m.bannerWidth (captured before the stdout redirect) rather
// than a fresh TermWidth() call.
func (m *harness) replaceBanner() {
	post := ""
	full := m.output.String()
	if m.bannerEnd > 0 && m.bannerEnd <= len(full) {
		post = full[m.bannerEnd:]
	}
	animated := AnimatedBanner(m.bannerWidth, m.shineCol)
	m.output.Reset()
	m.output.WriteString(animated)
	m.bannerEnd = m.output.Len()
	m.output.WriteString(post)
}

// setConversationContent pushes the current scrollback buffer into the
// viewport, wrapping it to the viewport's width first so long lines