Split blog into product announcements, provider announcements, and tutorials

[jeffreyaven]

Summary

Split the single blog into three @docusaurus/plugin-content-blog instances so each section has its own list page, sidebar and feed. A tag-based split was ruled out because the blog sidebar is built per plugin instance and cannot be filtered by tag.

Sections

Section	Instance id	Route	Content dir
Product announcements	product	/blog/product	blog/product
Provider announcements	providers	/blog/providers	blog/providers
Tutorials	tutorials	/blog/tutorials	blog/tutorials

Top-level /tutorials is not available: src/pages/tutorials.js already redirects it to /docs/tutorials.

Prerequisite (done before this issue is executed)

Each of the 105 existing posts gets exactly one marker tag in its tags front matter: product-announcement, provider-announcement or tutorial. The existing provider tag is not a reliable marker. Posts with zero or more than one marker tag should fail the move script.

Tasks

• Move each post into its section dir based on the marker tag, then drop the marker tag (the instance conveys the type). Slugs stay unchanged.
• Set blog: false in the classic preset and add three blog plugin instances, each with blogSidebarCount: 'ALL', its own blogSidebarTitle, blogTitle, blogDescription and feedOptions, and the existing postsPerPage, showReadingTime and editUrl settings.
• Share blog/authors.yml across the three instances (authorsMapPath) rather than copying it.
• Add a /blog landing page linking to the three sections with the latest posts from each.
• Generate 301 redirects in netlify.toml for every post: /blog/<slug> -> /blog/<section>/<slug>, plus the .md companion paths. Generate from front matter slugs, not filenames.
• Redirect old /blog/tags/* and /blog/page/* routes to /blog.
• Update sitemap ignorePatterns to cover /blog/*/tags/** and /blog/*/page/**.
• Update navbar ("More" dropdown) and footer links to expose the three sections.
• Fix internal links to old post URLs in docs, ai-content and blog (about 11 relative, 7 absolute stackql.io/blog/...). onBrokenLinks: 'throw' catches the relative ones; the absolute ones need a grep.
• @stackql/docusaurus-plugin-structured-data: src/index.js assumes /blog/<slug> (breadcrumb logic and isSkippedRoute for /blog/tags, /blog/page). Update for /blog/<section>/<slug>, release, and bump the version here.
• @stackql/docusaurus-plugin-aeo: replace the docusaurus-plugin-content-blog@default key in llmsTxt.instanceSections with the three new instance ids, and verify .md companions and the Ask AI button work for non-default blog instances.
• Update CLAUDE.md to describe the new blog structure.
• Trigger an Algolia recrawl after deploy.

Open questions

1. Old feed URLs (/blog/rss.xml, /blog/atom.xml, /blog/feed.json): redirect to the product announcements feed, or generate a combined feed at the old paths?
2. Naming: "Tutorials" in the nav currently means the docs tutorials at /docs/tutorials. Decide how the blog tutorials section is labelled and whether the two cross-link.

Acceptance criteria

• Each section list page and post page shows a sidebar containing only that section's posts.
• Every pre-existing post URL returns a 301 to its new URL.
• yarn build passes with onBrokenLinks: 'throw'.
• Each section has its own RSS/Atom feed.
• A post from each section emits valid Article and BreadcrumbList JSON-LD.
• llms.txt lists the three blog sections.
• Sitemap excludes tag and pagination routes for all three sections.