feat(seo): BlogPosting schema, FAQPage JSON-LD, extensible author system (#2284)

* feat(seo): BlogPosting schema, FAQPage JSON-LD, author system, AI crawler welcome

Blog structured data:
- Change @type Article to BlogPosting for all blog posts
- Author: Organization to Person with extensible default (Elie Habib)
- Add per-post author/authorUrl/authorBio/modifiedDate frontmatter fields
- Auto-extract FAQPage JSON-LD from FAQ sections in all 17 posts
- Show Updated date when modifiedDate differs from pubDate
- Add author bio section with GitHub avatar and fallback

Main app:
- Add commodity variant to middleware VARIANT_HOST_MAP and VARIANT_OG
- Add commodity.worldmonitor.app to sitemap.xml
- Shorten index.html meta description to 136 chars (was 161)
- Remove worksFor block from index.html author JSON-LD
- Welcome all bots in robots.txt (removed per-bot blocks, global allows)
- Update llms.txt: five variants listed, all 17 blog post URLs added

* fix(seo): scope FAQ regex to section boundary, use author-aware avatar

- extractFaqLd now slices only to the next ## heading (was: to end of body)
  preventing bold text in post-FAQ sections from being mistakenly extracted
- Avatar src now derived from DEFAULT_AUTHOR_GITHUB constant (koala73)
  only when using the default author; custom authors fall back to favicon
  so multi-author posts show a correct image instead of the wrong profile

index.html

@@ -9,7 +9,7 @@
     <!-- Primary Meta Tags -->
     <title>World Monitor - Real-Time Global Intelligence Dashboard</title>
     <meta name="title" content="World Monitor - Real-Time Global Intelligence Dashboard" />
-    <meta name="description" content="AI-powered real-time global intelligence dashboard with live news, markets, military tracking, infrastructure monitoring, and geopolitical data. OSINT in one view." />
+    <meta name="description" content="AI-powered real-time global intelligence dashboard with live news, markets, military tracking, and geopolitical data. OSINT in one view." />
     <meta name="keywords" content="AI intelligence, AI-powered dashboard, global intelligence, geopolitical dashboard, world news, market data, military bases, nuclear facilities, undersea cables, conflict zones, real-time monitoring, situation awareness, OSINT, flight tracking, AIS ships, earthquake monitor, protest tracker, power outages, oil prices, government spending, polymarket predictions" />
     <meta name="author" content="Elie Habib" />
     <meta name="theme-color" content="#0a0f0a" />
@@ -75,7 +75,7 @@
       "name": "World Monitor",
       "alternateName": "World Monitor",
       "url": "https://www.worldmonitor.app/",
-      "description": "Open-source real-time OSINT dashboard for geopolitical monitoring, conflict tracking, military flight tracking, maritime AIS, and global threat intelligence. Used by 2M+ people across 190+ countries.",
+      "description": "Open-source real-time global intelligence dashboard aggregating conflicts, military movements, markets, infrastructure, and geopolitical data. Used by 2M+ people across 190+ countries. Featured in WIRED.",
       "applicationCategory": "SecurityApplication",
       "operatingSystem": "Web, Windows, macOS, Linux",
       "offers": [
@@ -87,7 +87,6 @@
         "name": "Elie Habib",
         "url": "https://x.com/eliehabib",
         "jobTitle": "CEO",
-        "worksFor": { "@type": "Organization", "name": "Anghami", "url": "https://anghami.com" },
         "sameAs": ["https://x.com/eliehabib", "https://github.com/koala73"]
       },
       "featureList": [