fix: separate carousel header title from body text to avoid duplicate display

Previously the same `text` field was used for both header.title and body.text,
causing duplicate content to appear. Now `title` controls the header (defaults
to a space like Pastorini) and `text` controls the body independently.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/Types/Message.ts

@@ -467,6 +467,8 @@ export type CarouselCardInput = {
 export type CarouselMessageOptions = {
 	/** Cards in the carousel (2-10 recommended) */
 	cards: CarouselCardInput[]
+	/** Header title (displayed once above the carousel) */
+	title?: string
 	/** Main body text */
 	text?: string
 	/** Footer text */