fix: restore missing live-site page imagery

- recover and self-host HubSpot-injected page hero assets
- map source heroes to page and library layouts
- restore the consultation form background
- add page imagery auditing
- update asset inventory and migration documentation

www/src/layouts/BlogIndexLayout.astro

@@ -5,7 +5,7 @@ const languagePrefix = lang === 'en' ? '' : `/${lang}`;
 const canonical = `https://www.azinstitute4autism.com${languagePrefix}/library`;
 ---
 <BaseLayout title={title} description={description} canonical={canonical} lang={lang}>
-  <header class="library-banner"><div class="container"><p class="script-label">Welcome to</p><h1>{title}</h1></div></header>
+  <header class="library-banner"><div class="container"><div class="library-banner-copy"><p class="script-label">Welcome to</p><h1>{title}</h1></div></div></header>
   <section class="library-intro"><div class="container"><h2>Library</h2><p>{description}</p></div></section>
   <div class="container section library-layout"><slot /></div>
 </BaseLayout>