The wheel's arithmetic is checked in color.check.ts; nothing checked what a
drag across it sends. A new Playwright spec drags from the centre out to
three o'clock, counts the panel's publishes off the wire, and holds the disc
to one message at the release rather than one per pixel.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01K1moruzue2kTJd3uVisgNk
