… remove continue-on-error silent-failure trap

- Escape unescaped < in shell redirects (< seed.sql, << EOF) inside <pre><code> blocks
- Fix reversed closing tags (</pre></code> -> </code></pre>)
- Fix mismatched list closers (</ol> -> </ul>)
- Fix unclosed divs, stray </main>, duplicate article-waitlist wrappers
- Move <style> from body into <head> in new-cli-features-may-18-2026.html
- Fix unclosed <span class=cmd> nesting in clean-up-react-dead-code.html
- Remove continue-on-error: true from html-validate job (silent-failure trap)
- 32 tests pass