refactor(ui): rewrite Heading component to act as central typography system, fix line-heights, and apply to MDX pages

Former-commit-id: dc62485b60679b810b5f74bfb5a22915b7a62314

app/[locale]/[slug]/page.tsx

@@ -19,6 +19,7 @@ import { JobListingBlock } from '@/components/blocks/JobListingBlock';
 import { CallToAction } from '@/components/blocks/CallToAction';
 import { Button } from '@/components/ui/Button';
 
+
 const mdxComponents = {
   HomeHero,
   HomeSubCompanyTiles,
@@ -28,6 +29,7 @@ const mdxComponents = {
   JobListingBlock,
   CallToAction,
   Button,
+  Heading,
 };
 
 interface PageProps {