Optimise /odoo-ia/ and fix the site-wide 'null' header bug

/odoo-ia/ (279 impressions at position 6.8 for 'odo ia', zero clicks):
- H1 answers the query instead of describing the page: 'Odoo IA: que hace la
  inteligencia artificial en Odoo (y que no)'.
- Hero stats '60+ Recursos / 85% Automatizacion / 24/7 Operacion' replaced with
  the three honest routes: nativo / integracion / fuera. '85%' had no source.
- 'Empieza por aqui': five curated entry points, so the hub is a guide and not
  only a list of 55 links.
- Hosting CTA with utm_medium=hub-cta and a disclosure.
- FAQ (5 questions) + matching FAQPage schema. Answers are conditional on
  version and edition; no feature list is asserted, because odoo.com has no AI
  page to verify one against.

Separately, a real defect found while checking the render: 1,714 script blocks
across 840 pages called document.write(null) or set innerHTML = null, so the
header and footer rendered the literal text 'null'. Replaced with
createHeader()/createFooter(), which restores the real navigation on every
affected page.

de/odoo-ia/odoo-restaurantes-ia-hosteleria-2025/index.html

@@ -87,7 +87,7 @@
 </head>
 <body>
 <script src="/components/header.min.js"></script>
-<script>document.write(/*W6-static*/null);</script>
+    <script>document.write(createHeader());</script>
 <nav class="breadcrumbs"><a href="/">Startseite</a> › <a href="/de/odoo-ia/">Odoo KI</a> › <span>Restaurantes KI Hostelería</span></nav>
 <div class="article-content">
 <h1>Odoo Restaurantes KI: El System Que Predice Qué Van a Pedir Tus Clientes</h1>
@@ -111,7 +111,8 @@
 </div>
 <script src="/components/eeat.min.js"></script>
 <script>document.write(createEEAT({author: {name: "Equipo Odoo Expertos", title: "Consultora Senior en Sistemas ERP", experience: "15+ años"}, publishDate: "19 de julio de 2025"}));</script>
-<script src="/components/footer.min.js"></script><script>document.write(/*W6-static*/null);</script><script src="/js/cookie-banner.min.js"></script>
+<script src="/components/footer.min.js"></script>
+    <script>document.write(createFooter());</script><script src="/js/cookie-banner.min.js"></script>
     <script src="/js/plausible-events.js" defer></script>
 </body>
 </html>