Create a Flipbook PDF Reader widget that displays a PDF like a real book with page-flip animation (drag/click to turn pages). Users can upload a PDF or paste a URL. Include controls for next/prev, page thumbnails or page picker, zoom, and fullscreen. Add settings for single-page vs spread, LTR/RTL, cover page toggle, page flip speed, shadow/depth effect, and responsive behavior (swipe on mobile). Ensure accessibility (keyboard nav + reduced motion option) and a fallback to standard PDF view if flip mode can’t load.