createSpiralTube passed Math.max(96, turns * 38) as TubeGeometry's
tubularSegments, yielding fractional counts (5.8 -> 220.4, 6.4 -> 243.2).
TubeGeometry's trailing generateSegment indexes the Frenet-frame arrays
with that count, hits undefined and reads .x, throwing a TypeError that
aborts init and leaves the page stuck on the loading overlay forever.
Round the count to an integer; documented in the run note.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
