Add Schema.org JSON-LD structured data for SEO

Implemented comprehensive Schema.org structured data across the blog to improve SEO and enable rich snippets in search results.

Changes:
- Created JSON-LD helper component for safe schema rendering
- Added BlogPosting schema to blog posts with:
  * Article metadata (headline, description, image, dates)
  * Author and publisher information
  * Keywords and article sections from tags
- Added BreadcrumbList schema to blog posts for navigation
- Added WebSite and Organization schemas to root layout
  * Site-wide identity and branding
  * Search action for site search functionality
- Added CollectionPage schema to homepage
  * Blog collection metadata
- Added WebPage schema to static pages
  * Page metadata with dates and images

Benefits:
- Rich snippets in Google/Bing search results
- Better content understanding by search engines
- Article cards with images, dates, authors in SERPs
- Breadcrumb navigation in search results
- Improved SEO ranking signals

All schemas validated against Schema.org specifications and include proper Chinese language support.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

components/json-ld.tsx

@@ -0,0 +1,12 @@
+/**
+ * JSON-LD component for rendering structured data
+ * Safely serializes and injects Schema.org structured data into the page
+ */
+export function JsonLd({ data }: { data: Record<string, any> }) {
+  return (
+    <script
+      type="application/ld+json"
+      dangerouslySetInnerHTML={{ __html: JSON.stringify(data) }}
+    />
+  );
+}