[implexrr]

• Add a header toggle for the Warm Cream palette across the landing page, findings, and preview controls, with the dark palette as the default.
• Use a single surface for the landing comparison card and a short theme crossfade that respects reduced motion.
• Keep Little Sprout animated until scans finish or are cancelled, with a still sprite in reduced-motion mode.

Local verification passed: 142 tests, the production frontend build, isolated Chromium/Firefox/WebKit preview checks, and both dependency audits.