feat: complete newspaperui component library with docs site

- 18 React components (Layout/Section/Article/Layer/Masthead/Rule +
  Headline/Subhead/Kicker/BodyText/Quote/Byline/Dateline/Caption +
  Image/Figure/Video/PullQuote)
- Theme: warm off-white palette, Source Serif 4 / Cormorant Garamond /
  Inter / Noto Serif SC/JP, visual weight mapping, dark mode
- Docs: Landing page, 6 Blocks (zh/en/jp), component API docs
- GitHub Pages deployment via static export

Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

packages/docs/components/Sidebar.tsx

@@ -48,9 +48,9 @@ export function Sidebar() {
         fontFamily: 'var(--font-family-meta)',
         fontSize: '14px',
         position: 'sticky',
-        top: 0,
+        top: 65,
         alignSelf: 'flex-start',
-        maxHeight: '100vh',
+        maxHeight: 'calc(100vh - 65px)',
         overflowY: 'auto',
       }}
     >