Swap the default Quartz palette for warm parchment/terracotta/moss in
light mode and mossy-charcoal/cream in dark mode, picked to harmonize
with the castle logo. Replace icon.png and og-image.png with the
castle artwork (favicon + social previews). Extend PageTitle to render
the logo next to the site title in the sidebar via flex layout.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
