Tuned the edge layer and build pipeline for faster page loads

The marketing site is served from a static build by an edge layer. Both got tuned in the same pass:

• Third-party scripts defer at the layout level so they cannot block first paint.
• The edge layer got more aggressive caching headers on long-lived assets, a sensible brotli + gzip compression policy, and a sharper gzip_min_length threshold so even small responses compress when it is worth it.
• The build pipeline got the same treatment — chunk splitting tuned for cache hit rate, fonts subset to just the glyphs we use, SVG icons inlined where it saves a round trip.

The audit score line on the marketing site moved up across performance, accessibility, best practices and SEO. Not from one dramatic fix, but from a dozen small ones stacked together.