Document seed mode's palette pick used to ask the user to imagine colors
from words. Add a visual-cues pipeline: compose four-hex palettes from the
brief (mood, references, PRODUCT.md), generate a hero scene plus a cream
artifact sheet per concept, crop the sheet into isolated artifacts, and
write cues.json so the user can pick a direction by eye.
Co-authored-by: Cursor <cursoragent@cursor.com>