site: bring the brain-inspired HUD showcase to opennorve.github.io/CogniFold (#31)

Replaces docs-site/index.html with the HUD redesign (three-card landing:
Title+stats | Design Philosophy+CLS | Results leaderboard; Fraunces display
serif; brain favicon; Memory Map page with per-region figure hover) and adds
the brain render + region figures. All canonical/OG/Twitter URLs and the
GitHub link now point to opennorve / OpenNorve. Pages already deploys from
main, so merging publishes to https://opennorve.github.io/CogniFold/.

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: wsuli615