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/next.config.mjs

@@ -3,6 +3,9 @@ import rehypePrettyCode from 'rehype-pretty-code';
 
 /** @type {import('next').NextConfig} */
 const nextConfig = {
+  output: 'export',
+  basePath: process.env.NEXT_PUBLIC_BASE_PATH || '',
+  images: { unoptimized: true },
   pageExtensions: ['js', 'jsx', 'md', 'mdx', 'ts', 'tsx'],
   transpilePackages: ['@newspaperui/components', '@newspaperui/theme', '@newspaperui/utils'],
 };