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/Services.jsx

@@ -30,12 +30,13 @@ export default function Services({
   eyebrow = 'services --price-list',
   title = 'Услуги IT-аутсорсинга и техподдержки: прайс-лист',
   desc = 'Гибкие тарифы для бизнеса любого масштаба. Возможна индивидуальная настройка под ваши задачи.',
+  headingLevel = 'h2',
 }) {
   const list = limit ? categories.slice(0, limit) : categories;
 
   return (
     <section id="services" className="max-w-6xl mx-auto px-5 sm:px-8 py-20">
-      <SectionHeading eyebrow={eyebrow} title={title} desc={desc} />
+      <SectionHeading eyebrow={eyebrow} title={title} desc={desc} level={headingLevel} />
 
       {list.length === 0 && <p className="text-sm text-slate-400">Прайс-лист пока пуст.</p>}