seo(website): add JSON-LD Article markup to blog posts and BreadcrumbList to docs

[ajitpratap0]

Problem

Blog posts lack Article JSON-LD (datePublished, author, description). Doc pages lack BreadcrumbList JSON-LD. These are significant missed opportunities for rich search results.

The layout already has SoftwareApplication JSON-LD (added in the audit quick-wins PR), but page-level structured data is still missing.

Fix

1. In blog/[slug]/page.tsx, add Article JSON-LD script:

{
  "@context": "https://schema.org",
  "@type": "Article",
  "headline": "<post title>",
  "datePublished": "<post date>",
  "description": "<post description>",
  "author": { "@type": "Organization", "name": "GoSQLX" },
  "publisher": { "@type": "Organization", "name": "GoSQLX", "url": "https://gosqlx.dev" }
}

2. In docs/[...slug]/page.tsx, add BreadcrumbList JSON-LD based on the category and page title.