Adds feed support for kind 2473 (bird-by-ear detections) and kind 30621
(user-drawn star figures) from Birdstar. Detections render as species
cards using the existing Wikidata + Wikipedia summary hooks; constellations
render as gnomonically-projected SVG star-maps backed by the Hipparcos
catalog from d3-celestial. The 1.1 MB catalog is code-split via lazy() so
it only loads when a constellation event is actually viewed.
Alex Gleason