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/compress-pdf.html

@@ -27,7 +27,7 @@
     />
 
     <!-- Canonical URL -->
-    <link rel="canonical" href="https://www.bentopdf.com/compress-pdf.html" />
+    <link rel="canonical" href="https://www.bentopdf.com/compress-pdf" />
 
     <!-- Open Graph / Facebook / LinkedIn -->
     <meta property="og:type" content="website" />
@@ -589,11 +589,6 @@
           "price": "0",
           "priceCurrency": "USD"
         },
-        "aggregateRating": {
-          "@type": "AggregateRating",
-          "ratingValue": "4.7",
-          "ratingCount": "3421"
-        },
         "featureList": [
           "Reduce PDF file size",
           "Multiple compression algorithms",