pages.yaml's title/description are interpolated as plain strings into <title>
and <meta name="description">, so html/template escapes them. Writing an HTML
entity in the YAML therefore escapes it a second time and the user sees the
source. Live on main right now:
<meta name="description" content="... a &plusmn;7-day seasonal window ...">
<title>Weather &amp; climate glossary: ...</title>
which renders as a literal "±7-day" in the SERP snippet and "&" in
the browser tab, on the about and glossary pages. The Python->Go rewrite did not
change this: the entities live in the shared data file and both engines
autoescape identically.
glossary.yaml is deliberately NOT touched. Its `body` is typed template.HTML and
rendered raw (glossary_term.html.tmpl), so the entities and <b> tags there are
correct and would break if "fixed".
The regression test runs against the real content dir, which the frontend
Dockerfile already copies into the builder stage, so it gates the image rather
than only local runs.
