The Color Guide's library button opens a Limit to Library popup (None,
Document Swatches, the colour libraries): every harmony colour and
variation snaps to the nearest colour there (CIEDE2000), cached per
inputs so the grid isn't re-snapped every frame. `color.harmony` takes
`limitTo`, `ui.colorGuideLimit` sets the panel's limit, and Recolor
Artwork's Limit to Library also offers the document's swatches (one
shared engine helper, swatchlib::limit_palette).
Edit or Apply Colors opens Recolor with the harmony colours limited to
the same library; with no art selected the colours are the rows and OK
saves them as a new colour group.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>