feat(seo): canonicalize URLs, clean structured data, add audit gate

- Canonicals/hreflang/og point to www.bentopdf.com everywhere
- Drop fake aggregateRating; add Organization + breadcrumb JSON-LD
- Sitemap: filter 404/wasm-settings, mtime-based lastmod
- Rename locale ua → uk (correct ISO 639-1)
- Self-hoster: SITE_URL build arg, ROBOTS_NOINDEX runtime env
- Simple Mode indexable by default
- nginx: collapse .html and /index.html via 301
- SEO audit script + PR gate; runtime config noise fixed
- a11y contrast fix; language switcher gets search + scroll
- robots.txt: drop Crawl-delay

src/pages/scanner-effect.html

@@ -4,7 +4,6 @@
     <meta charset="UTF-8" />
     <meta name="viewport" content="width=device-width, initial-scale=1.0" />
 
-    <title>Scanner Effect Online Free - Scanner Effect Tool | BentoPDF</title>
     <meta
       name="title"
       content="Scanner Effect Online Free - Scanner Effect Tool | BentoPDF"
@@ -23,7 +22,7 @@
       content="index, follow, max-image-preview:large, max-snippet:-1, max-video-preview:-1"
     />
 
-    <link rel="canonical" href="https://www.bentopdf.com/scanner-effect.html" />
+    <link rel="canonical" href="https://www.bentopdf.com/scanner-effect" />
 
     <meta property="og:type" content="website" />
     <meta property="og:url" content="https://www.bentopdf.com/scanner-effect" />
@@ -607,11 +606,6 @@
           "@type": "Offer",
           "price": "0",
           "priceCurrency": "USD"
-        },
-        "aggregateRating": {
-          "@type": "AggregateRating",
-          "ratingValue": "4.7",
-          "ratingCount": "2143"
         }
       }
     </script>