P4.2: Structured Data Optimization (BlogPosting + BreadcrumbList)

[jubalm]

Context

P4.2 from optimization tasks — SEO/Accessibility priority tier.

Task

Expand structured data schema coverage:

• Add BlogPosting schema to blog post pages (blog/[...slug].astro) with title, author, datePublished, dateModified, image, articleBody
• Add BreadcrumbList schema to Layout.astro for navigation context
• Ensure all dates are ISO 8601 format
• Validate with Google's Rich Results Test

Files to Modify

• src/layouts/BlogLayout.astro
• src/layouts/Layout.astro
• Tests: validate with Google Rich Results Test

Notes

• Deferred from optimization-tasks PR to avoid scope creep
• Can be done independently of P4.1 (reduce motion support)