Document the new Pro PDF Viewer widget

Adds the docs-site page and the website marketing copy for the PDF
Viewer widget shipped in Pro 20260908.1.

- docs: full widget guide (source, zoom, toolbar, styling, gotchas),
  listed in the Pro getting-started widget index, with the usual two
  placeholder screenshots to be replaced with real captures.
- getting-started: PDF Viewer noted as having no WooCommerce or ACF
  dependency.
- marketing: widget page plus a "What's included" entry and an updated
  strapline on the Pro overview.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

marketing/dotjuice-elementor-tools-pro/overview.md

@@ -1,4 +1,4 @@
-The premium widget set for serious WooCommerce stores — AJAX product filtering, a fully custom cart, quick view, custom product tabs, frontend ACF forms, and watermark-free screenshots.
+The premium widget set for serious WooCommerce stores — AJAX product filtering, a fully custom cart, quick view, custom product tabs, frontend ACF forms, an on-brand PDF viewer, and watermark-free screenshots.
 
 ### Built for stores that have outgrown the basics
 
@@ -14,6 +14,7 @@ The free Dotjuice Elementor Tools plugin covers the everyday styling gaps in Woo
 
 **Woo Custom Product Tabs** — a full rebuild of the WooCommerce product tabs area as a styleable desktop-tabs/mobile-accordion component: add unlimited custom tabs, show or hide any custom tab per product by category, tag, brand or attribute, and style deep into your reviews and rating form.
 
+**PDF Viewer** — display brochures, manuals, price lists and menus directly on your pages in a fully styleable viewer with page navigation, zoom, fullscreen, download and print, instead of a download link or the browser's own unstyleable PDF plugin.
 
 **ACF Frontend Form** — let visitors edit Advanced Custom Fields content directly from the front end, using ACF's own native form interface, no admin access required.