feat(www): add 10 scheduled blog posts (May 4 - Jun 3) (#811)

Adds 10 new SEO-optimized blog posts on a Mon/Wed cadence using the
future-dated publishedAt scheduling added in #810. Each post is
1,500-2,500+ prose words with a TLDRBox, real SonicJS code examples,
internal doc links, and a DALL-E hero image:

- 2026-05-04 tutorials/building-rest-api-with-sonicjs
- 2026-05-06 tutorials/deploy-sonicjs-to-cloudflare-workers
- 2026-05-11 tutorials/creating-custom-collections-in-sonicjs
- 2026-05-13 tutorials/sonicjs-file-uploads-with-r2
- 2026-05-18 guides/using-sonicjs-with-nextjs
- 2026-05-20 guides/sonicjs-plugins-extending-your-cms
- 2026-05-25 comparisons/sonicjs-vs-wordpress
- 2026-05-27 comparisons/sonicjs-vs-ghost
- 2026-06-01 deep-dives/sonicjs-d1-database-deep-dive
- 2026-06-03 deep-dives/sonicjs-plugin-architecture-deep-dive

Posts stay hidden in production (listings, RSS, sitemap, direct URLs)
until each publishedAt date passes and the next deploy runs.

Co-authored-by: Claude Opus 4.7 <noreply@anthropic.com>

Author: lane711