Radial Burst Hero
A Stripe-style hero block: an interactive fiber-optic radial burst on canvas. Fine glowing rays stream out of a bottom-center origin in a wide fan, each one continuously growing, over-extending, fading, and regenerating with fresh angle/length/speed/opacity, with a single glowing dot riding each fiber's tip. Hovering the middle or tip of a fiber makes it (and its neighbours) brighten, stretch, and bend toward the cursor, then ease back to their drift; the dense zone near the origin stays calm. The burst sits in a short lower band, masked so it fades out below the headline. Ships with six time-of-day themes (Pre-dawn, Sunrise, Daytime, Dusk, Sunset, Night) and an in-block switcher; the background crossfades and the burst colors lerp between themes. devicePixelRatio-aware, keyboard-accessible switcher, honors `prefers-reduced-motion` (renders a calm static frame), and uses `motion` for the intro, theme blend, and dropdown.