fix(homepage): align hero width to content token, soften h1 code weight

Hero used a hardcoded max-width: 72rem while the content section below
used theme.layout.contentWidth (120ch), so the hero rendered slightly
narrower than the section beneath it. Both now read from the same token.

Inline code inside an h1 was inheriting font-weight 700 from the display
heading, which renders heavy in Google Sans Code — especially the angle
brackets in <Component>. Pin h1 code to semibold (600).

Author: quantizor

components/GlobalStyles.tsx

@@ -174,6 +174,10 @@ const GlobalStyles = createGlobalStyle`
     padding: 0.15em 0.3em;
   }
 
+  h1 code {
+    font-weight: ${theme.fontWeight.semibold};
+  }
+
   /* ── Lists ────────────────────────────────────────────────── */
   ul, ol {
     padding-left: 0;

components/HomepageHeroEditor.tsx

@@ -135,7 +135,7 @@ export const HeroContent = styled.div`
   box-sizing: border-box;
   font-family: ${font.sans};
   margin: 0 auto;
-  max-width: 72rem;
+  max-width: ${theme.layout.contentWidth};
   padding: ${theme.space[16]} ${theme.layout.gutterFluid} 0;
   width: 100%;