number | string
Optional explicit height. Accepted for ergonomic call-sites that want
to size the bloom inline (e.g. `<BloomArt height={240}/>`). The SVG
itself scales via `preserveAspectRatio="xMidYMid slice"`, so height is
forwarded into `style.height` on the wrapping `<div>`. When omitted,
the bloom fills its parent (the canonical pattern — wrap in a sized
container — still works unchanged).