[Vondry]

Summary

Two fixes where the README didn't match the code. This PR changes the README and a comment in config/config.yaml. There are no code changes.

Changes

• Template override path. The README said to uncomment meta: _metatags.html.twig, but the lines that config/config.yaml ships read meta: _partials/_metatags.html.twig. Users who followed both got a "template not found" error. Both now use _metatags.html.twig, so the copy can sit in the root of the theme and nobody has to create a _partials folder. A new comment in config.yaml and a sentence in the README explain that the path is relative to the theme folder, with a subfolder example (partials/seo/_metatags.html.twig).
• Fallback order. "Override → SEO field → record fields → defaults" is only fully true for title() and description(). The README now says which values each step applies to:
  • the SEO field doesn't store image;
  • only title, description and image fall back to the record's own fields (fields.keywords isn't used for output);
  • after the default values, the title falls back to sitename, the description to payoff, canonical to Bolt's canonical URL, ogtype to website, robots to index, follow, and image to the record's image as Bolt finds it;
  • on listings the title falls back to the content type name, and on taxonomy pages it is "Overview for …".

Existing sites keep their copy of appolo-boltseo.yaml, because Bolt never updates it. The changed comment only affects new installs.

Verified

• The fallback steps were checked against Seo::title(), description(), keywords(), image(), robots(), ogtype() and canonical().
• Bolt adds the theme folder (plus theme/template_directory, if set) to Twig's template paths in TwigAwareController::setTwigLoader(). So templates.meta is resolved relative to the theme, and a bare filename is found in the theme root.
• Two production sites use meta: partials/seo/_metatags.html.twig, with the file at public/theme/<theme>/partials/seo/_metatags.html.twig. This confirms that a subfolder works.
• config/config.yaml still parses, and templates stays commented out by default.