Fix missing H1 on list-style pages via SectionHeading template

SectionHeading always rendered its title as <h2>, so every page whose
only heading came from a shared section component (services hub,
promotions, cases, faq, contact, reviews, blog list) had no <h1> at
all. Add a level prop (default h2) and pass headingLevel="h1" from
each page where that section is the page's own top-level heading.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013otXCiTZsxdZ4SJKZ9wUky

public-site/components/sections/Faq.jsx

@@ -23,13 +23,13 @@ function FaqItem({ item }) {
   );
 }
 
-export default function Faq({ faqs, limit, moreHref }) {
+export default function Faq({ faqs, limit, moreHref, headingLevel = 'h2' }) {
   if (faqs.length === 0) return null;
   const list = limit ? faqs.slice(0, limit) : faqs;
 
   return (
     <section id="faq" className="max-w-3xl mx-auto px-5 sm:px-8 py-20">
-      <SectionHeading eyebrow="faq --common" title="Частые вопросы" />
+      <SectionHeading eyebrow="faq --common" title="Частые вопросы" level={headingLevel} />
       <Reveal>
         <div>
           {list.map((item) => (