feat: shared logo rotation, palette tuning, accent unification, favicon

PlatonicLogo:
- Shared rotation singleton (globalThis-persisted for HMR) syncs all
  instances: rotation, shape, prefs, drag state
- Azimuth-based face coloring with even-spaced palette redistribution
  per solid size (smooth gradient at 20, max spread at 4)
- Faces use theme.palette (auto light/dark) instead of hardcoded logoPalette
- qNorm separated from qMul, rAF string-cache skip, prefsLoaded in subscribe
- CustomEvent replaced with direct ref-based function call

Palette:
- Light palette regenerated from red seed oklch(0.72 0.27 30), separate+harmonize
  pipeline, ΔE 8.58
- Dark palette harmonized via qlab, L-0.03 darkened, ΔE 8.69
- Dark mode code neutrals cooled to hue 270

Accent & links:
- Both modes derive accent from palette P[13] with L-shifted variants on same hue
- Links: accent at rest, accentDark on hover, matching underline color
- Sidebar active state uses accent (not accentLight), accentDark on hover
- NextPage title: accent color with solid underline on hover

Favicon: new SVG with dynamic 3D angle, 10 palette-colored icosahedron faces

Author: quantizor

app/layout.tsx

@@ -85,7 +85,7 @@ const themeScript = `
         d.dataset.theme = 'dark';
       }
     } catch (e) {}
-    d.setAttribute('data-hero-logo-visible', '');
+    if (location.pathname === '/') d.setAttribute('data-hero-logo-visible', '');
   })();
 `;
 

components/HomepageHeroEditor.tsx

@@ -182,7 +182,6 @@ const EditorColumn = styled.div`
 
 const HeroRight = styled.div`
   border: 1px solid ${theme.color.border};
-  box-shadow: 0 1px 3px ${theme.color.shadow};
   text-align: left;
   width: 100%;
   position: relative;

components/Link.tsx

@@ -14,10 +14,11 @@ export type LinkVariant = 'inline' | 'heading' | 'block' | 'unstyled';
 
 // Inline: colored text with dotted underline that turns solid on hover
 export const inlineStyle = css`
-  color: ${theme.color.accentLight};
+  color: ${theme.color.accent};
+  font-weight: ${theme.fontWeight.medium};
   cursor: pointer;
   text-decoration: underline dotted;
-  text-decoration-color: ${theme.color.linkUnderline};
+  text-decoration-color: ${theme.color.accent};
   text-underline-offset: 3px;
   transition:
     color ${theme.duration.fast},
@@ -26,9 +27,9 @@ export const inlineStyle = css`
 
   &:hover,
   &:focus-visible {
-    color: ${theme.color.accentLighter};
+    color: ${theme.color.accentDark};
     text-decoration-style: solid;
-    text-decoration-color: ${theme.color.linkUnderlineHover};
+    text-decoration-color: ${theme.color.accentDark};
   }
 `;