feat: auto-opening brochure modal with mintel/mail delivery

- implemented BrochureDeliveryEmail template

- created AutoBrochureModal wrapper with 5s delay

- updated layout.tsx and BrochureCTA to use new success state

- added tests/brochure-modal.test.ts e2e test

next.config.mjs

@@ -79,7 +79,7 @@ const nextConfig = {
       },
       {
         key: 'Strict-Transport-Security',
-        value: 'max-age=63072000; includeSubDomains; preload',
+        value: isProd ? 'max-age=63072000; includeSubDomains; preload' : 'max-age=0',
       },
     ];