Newsletter / email subscription banner — title, description, email input, and submit action on a full-width surface. For an inline signup CTA band; the prose-width form companion is subscribe-section.

• src/components/registry/components/heros-and-promos/subscription-banner.tsx→components/registry/components/heros-and-promos/subscription-banner.tsx
• src/components/registry/components/heros-and-promos/subscription-banner.recipe.ts→src/recipes/subscription-banner.recipe.ts