- Restore HTML link extraction in LinkValidator (removed in a83634d
under the false premise that post bodies are raw markdown; they
are HTML rendered by NimblePublisher at compile time). The missing
regex made extract_links/1 find zero links, silently disabling
compile-time validation.
- Support /blog/{blog_id}/tag/{tag} links: validate blog ID,
require non-empty tag (tags are user-defined, e.g. pi.dev).
- Fix invalid links in two posts: tag/Pi.dev -> tag/pi.dev,
2026-07-13-synthetic-tdd.md -> synthetic-tdd.
- Fix test warnings: use Plug.Test deprecation, unused import,
runtime-defined TestBlogValid module.
- Add regression tests for HTML extraction and tag page links.
Goal: have a personal blog, and try out another point in the 'modular
app design with elixir' space.
Designing OTP systems with elixir had some interesting ideas.