Optimize documentation for SEO and LLMs

[mintlify]

Enhanced all 18 documentation pages with keyword-rich meta descriptions, improved titles, and structured content sections. Added explicit context and semantic clarity throughout to improve discoverability for search engines and AI systems.

Changes

Meta descriptions updated:

• guides/introduction.mdx
• guides/quickstart.mdx
• guides/integrations/nextjs.mdx
• guides/integrations/astro.mdx
• guides/integrations/tanstack.mdx
• guides/features/webhooks.mdx
• guides/features/import.mdx
• guides/features/extra/reading-time.mdx
• api/introduction.mdx
• api/getting-started.mdx
• api/endpoint/posts.mdx
• api/endpoint/post.mdx
• api/endpoint/tags.mdx
• api/endpoint/categories.mdx
• api/endpoint/authors.mdx
• api/pagination.mdx
• api/rate-limits.mdx
• api/types.mdx

Content improvements:

• Added "Overview" and "What is..." sections to key pages
• Improved internal linking with proper markdown links
• Enhanced semantic clarity with specific terminology
• Added contextual introductions before technical details